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Sambri I, Ferniani M, Ballabio A. Ragopathies and the rising influence of RagGTPases on human diseases. Nat Commun 2024; 15:5812. [PMID: 38987251 PMCID: PMC11237164 DOI: 10.1038/s41467-024-50034-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Accepted: 06/27/2024] [Indexed: 07/12/2024] Open
Abstract
RagGTPases (Rags) play an essential role in the regulation of cell metabolism by controlling the activities of both mechanistic target of rapamycin complex 1 (mTORC1) and Transcription factor EB (TFEB). Several diseases, herein named ragopathies, are associated to Rags dysfunction. These diseases may be caused by mutations either in genes encoding the Rags, or in their upstream regulators. The resulting phenotypes may encompass a variety of clinical features such as cataract, kidney tubulopathy, dilated cardiomyopathy and several types of cancer. In this review, we focus on the key clinical, molecular and physio-pathological features of ragopathies, aiming to shed light on their underlying mechanisms.
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Affiliation(s)
- Irene Sambri
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, (NA), Italy
- Scuola Superiore Meridionale (SSM, School of Advanced Studies), Genomics and Experimental Medicine Program (GEM), Naples, Italy
| | - Marco Ferniani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Andrea Ballabio
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, (NA), Italy.
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA.
- Medical Genetics Unit, Department of Medical and Translational Science, Federico II University, Naples, Italy.
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2
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Tang X, Liu H, Chang L, Wang X, Liu Q, Tang Z, Xia Q, Zhao P. A strategy for improving silk yield and organ size in silk-producing insects. FEBS J 2024. [PMID: 38923388 DOI: 10.1111/febs.17193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 04/24/2024] [Accepted: 05/22/2024] [Indexed: 06/28/2024]
Abstract
Insect silks possess excellent biodegradability, biocompatibility and mechanical properties, and have numerous applications in biomedicine and tissue engineering. However, the application of silk fiber is hindered by its limited supply, especially from non-domesticated insects. In the present study, the silk yield and organ size of Bombyx mori were significantly improved through genetic manipulation of the target of rapamycin complex 1 (TORC1) pathway components. Silk protein synthesis and silk gland size were decreased following rapamycin treatment, inhibiting the TORC1 signaling pathway both in vivo and ex vivo. The overexpression of posterior silk gland-specific Rheb and BmSLC7A5 improved silk protein synthesis and silk gland size by activating the TORC1 signaling pathway. Silk yield in BmSLC7A5-overexpression silkworms was significantly increased by approximately 25%. We have demonstrated that the TORC1 signaling pathway is involved in the transcription and translation of silk genes and transcriptional activators via phosphorylation of p70 S6 kinase 1 and 4E-binding protein 1. Our findings present a strategy for increasing silk yield and organ size in silk-producing insects.
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Affiliation(s)
- Xin Tang
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing, China
- Chongqing Key Laboratory of the Innovative Chinese Materia Medica & Health Intervention, Chongqing Academy of Chinese Materia Medica, China
| | - Huawei Liu
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing, China
- Key Laboratory for Germplasm Creation in Upper Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, Chongqing, China
| | - Li Chang
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing, China
- Institute for Brain Science and Disease, Chongqing Medical University, China
| | - Xin Wang
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing, China
- Key Laboratory for Germplasm Creation in Upper Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, Chongqing, China
| | - Qingsong Liu
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing, China
- Key Laboratory for Germplasm Creation in Upper Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, Chongqing, China
| | - Zhangchen Tang
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing, China
- Key Laboratory for Germplasm Creation in Upper Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, Chongqing, China
| | - Qingyou Xia
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing, China
- Key Laboratory for Germplasm Creation in Upper Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, Chongqing, China
| | - Ping Zhao
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing, China
- Key Laboratory for Germplasm Creation in Upper Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, Chongqing, China
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3
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Liu J, Gao J, Lu P, Wang Y, Xing S, Yan Y, Han R, Hao P, Li X. Mesenchymal Stem Cell-Derived Exosomes as Drug Carriers for Delivering miRNA-29b to Ameliorate Inflammation in Corneal Injury Via Activating Autophagy. Invest Ophthalmol Vis Sci 2024; 65:16. [PMID: 38856990 PMCID: PMC11166224 DOI: 10.1167/iovs.65.6.16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 05/17/2024] [Indexed: 06/11/2024] Open
Abstract
Purpose Corneal injury (CI) resulting in corneal opacity remains a clinical challenge. Exosomes (Exos) derived from bone marrow mesenchymal stem cells (BMSCs) have been proven effective in repairing various tissue injuries and are also considered excellent drug carriers due to their biological properties. Recently, microRNA-29b (miR-29b) was found to play an important role in the autophagy regulation which correlates with cell inflammation and fibrosis. However, the effects of miR-29b and autophagy on CI remain unclear. To find better treatments for CI, we used Exos to carry miR-29b and investigated its effects in the treatment of CI. Methods BMSCs were transfected with miR-29b-3p agomir/antagomir and negative controls (NCs) to obtain Exos-29b-ago, Exos-29b-anta, and Exos-NC. C57BL/6J mice that underwent CI surgeries were treated with Exos-29b-ago, Exos-29b-anta, Exos-NC, or PBS. The autophagy, inflammation, and fibrosis of the cornea were estimated by slit-lamp, hematoxylin and eosin (H&E) staining, immunofluorescence, RT‒qPCR, and Western blot. The effects of miR-29b-3p on autophagy and inflammation in immortalized human corneal epithelial cells (iHCECs) were also investigated. Results Compared to PBS, Exos-29b-ago, Exos-29b-anta, and Exos-NC all could ameliorate corneal inflammation and fibrosis. However, Exos-29b-ago, which accumulated a large amount of miR-29b-3p, exerted excellent potency via autophagy activation by inhibiting the PI3K/AKT/mTOR pathway and further inhibited corneal inflammation via the mTOR/NF-κB/IL-1β pathway. After Exos-29b-ago treatment, the expressions of collagen type III, α-smooth muscle actin, fibronectin, and vimentin were significantly decreased than in other groups. In addition, overexpression of miR-29b-3p prevented iHCECs from autophagy impairment and inflammatory injury. Conclusions Exos from BMSCs carrying miR-29b-3p can significantly improve the therapeutic effect on CI via activating autophagy and further inhibiting corneal inflammation and fibrosis.
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Affiliation(s)
- Jinghua Liu
- School of Medicine, Nankai University, Tianjin, China; Nankai University Affiliated Eye Hospital, Tianjin, China
- Tianjin Eye Hospital, Tianjin Key Lab of Ophthalmology and Vision Science, Tianjin Eye Institute, Tianjin, China
| | - Juan Gao
- Tianjin Eye Hospital, Tianjin Key Lab of Ophthalmology and Vision Science, Tianjin Eye Institute, Tianjin, China
| | - Ping Lu
- Tianjin Eye Hospital, Tianjin Key Lab of Ophthalmology and Vision Science, Tianjin Eye Institute, Tianjin, China
| | - Yuchuan Wang
- Tianjin Eye Hospital, Tianjin Key Lab of Ophthalmology and Vision Science, Tianjin Eye Institute, Tianjin, China
| | - Shulei Xing
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China
| | - Yarong Yan
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China
| | - Ruifang Han
- Tianjin Eye Hospital, Tianjin Key Lab of Ophthalmology and Vision Science, Tianjin Eye Institute, Tianjin, China
| | - Peng Hao
- Tianjin Eye Hospital, Tianjin Key Lab of Ophthalmology and Vision Science, Tianjin Eye Institute, Tianjin, China
| | - Xuan Li
- School of Medicine, Nankai University, Tianjin, China; Nankai University Affiliated Eye Hospital, Tianjin, China
- Tianjin Eye Hospital, Tianjin Key Lab of Ophthalmology and Vision Science, Tianjin Eye Institute, Tianjin, China
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China
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Zhang W, Dong C, Xiong S. Mycobacterial SapM hampers host autophagy initiation for intracellular bacillary survival via dephosphorylating Raptor. iScience 2024; 27:109671. [PMID: 38646170 PMCID: PMC11031826 DOI: 10.1016/j.isci.2024.109671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Revised: 02/01/2024] [Accepted: 04/02/2024] [Indexed: 04/23/2024] Open
Abstract
Secreted acid phosphatase (SapM) is an immunomodulator of Mycobacterium tuberculosis (Mtb) and consequently plays a crucial role in disease onset and development upon infection. Importantly, the virulence of SapM has rendered SapM an attractive target for drug development. However, the mechanism underlying the role of SapM in facilitating bacillary survival remains to be fully elucidated. In this context, the present study demonstrated that SapM hampered cellular autophagy to facilitate bacillary survival in mycobacterial-infected macrophages. Mechanically, SapM interacted with Raptor and was localized to the subcellular lysosomal organelle, causing the dephosphorylation of Raptor at the Ser792 position, resulting in mTORC1 hyperactivity and the subsequent autophagy inhibition. Consistent with this, SapM blocked the autophagy initiation and mitigated lung pathology in vivo. These findings highlighted the role of Raptor as a significant substrate of SapM for inhibiting autophagy, which is a novel clue for developing a treatment against tuberculosis.
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Affiliation(s)
- Wei Zhang
- Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences, Suzhou Medical College of Soochow University, Suzhou 215123, China
| | - Chunsheng Dong
- Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences, Suzhou Medical College of Soochow University, Suzhou 215123, China
- Key Laboratory of Geriatric Diseases and Immunology, Ministry of Education, Institutes of Biology and Medical Sciences, Suzhou Medical College of Soochow University, Suzhou 215123, China
| | - Sidong Xiong
- Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences, Suzhou Medical College of Soochow University, Suzhou 215123, China
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Rameh LE, York JD, Blind RD. Multiple inositol phosphate species enhance stability of active mTOR. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.01.592113. [PMID: 38746235 PMCID: PMC11092565 DOI: 10.1101/2024.05.01.592113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Mechanistic Target of Rapamycin (mTOR) binds the small metabolite inositol hexakisphosphate (IP6) as shown in structures of mTOR, however it remains unclear if IP6, or any other inositol phosphate species, can activate mTOR kinase activity. Here, we show that multiple, exogenously added inositol phosphate species (IP6, IP5, IP4 and IP3) can all enhance the ability of mTOR and mTORC1 to auto-phosphorylate and incorporate radiolabeled phosphate into peptide substrates in in vitro kinase reactions. Although IP6 did not affect the apparent KM of mTORC1 for ATP, monitoring kinase activity over longer reaction times showed increased product formation, suggesting inositol phosphates stabilize an active form of mTORC1 in vitro. The effects of IP6 on mTOR were reversible, suggesting IP6 bound to mTOR can be exchanged dynamically with the free solvent. Interestingly, we also observed that IP6 could alter mTOR solubility and electrophoretic mobility in SDS-PAGE in the presence of manganese, suggesting divalent cations may play a role in inositol phosphate regulation of mTOR. Together, these data suggest for the first time that multiple inositol phosphate species (IP4, IP5 and IP6) can dynamically regulate mTOR and mTORC1 by promoting a stable, active state of the kinase. Our data suggest that studies of the dynamics of inositol phosphate regulation of mTOR are well justified.
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Affiliation(s)
- Lucia E. Rameh
- University of South Alabama, Department of Biochemistry and Molecular Biology, Mobile, AL 36688
- Vanderbilt University School of Medicine, Department of Biochemistry, Nashville, TN 37232
- Vanderbilt University Medical Center, Department of Medicine, Division of Diabetes, Endocrinology and Metabolism, Nashville, TN 37232
| | - John D. York
- Vanderbilt University School of Medicine, Department of Biochemistry, Nashville, TN 37232
| | - Raymond D. Blind
- Vanderbilt University School of Medicine, Department of Biochemistry, Nashville, TN 37232
- Vanderbilt University Medical Center, Department of Medicine, Division of Diabetes, Endocrinology and Metabolism, Nashville, TN 37232
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Feng R, Liu F, Li R, Zhou Z, Lin Z, Lin S, Deng S, Li Y, Nong B, Xia Y, Li Z, Zhong X, Yang S, Wan G, Ma W, Wu S, Songyang Z. The rapid proximity labeling system PhastID identifies ATP6AP1 as an unconventional GEF for Rheb. Cell Res 2024; 34:355-369. [PMID: 38448650 PMCID: PMC11061317 DOI: 10.1038/s41422-024-00938-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Accepted: 02/02/2024] [Indexed: 03/08/2024] Open
Abstract
Rheb is a small G protein that functions as the direct activator of the mechanistic target of rapamycin complex 1 (mTORC1) to coordinate signaling cascades in response to nutrients and growth factors. Despite extensive studies, the guanine nucleotide exchange factor (GEF) that directly activates Rheb remains unclear, at least in part due to the dynamic and transient nature of protein-protein interactions (PPIs) that are the hallmarks of signal transduction. Here, we report the development of a rapid and robust proximity labeling system named Pyrococcus horikoshii biotin protein ligase (PhBPL)-assisted biotin identification (PhastID) and detail the insulin-stimulated changes in Rheb-proximity protein networks that were identified using PhastID. In particular, we found that the lysosomal V-ATPase subunit ATP6AP1 could dynamically interact with Rheb. ATP6AP1 could directly bind to Rheb through its last 12 amino acids and utilizes a tri-aspartate motif in its highly conserved C-tail to enhance Rheb GTP loading. In fact, targeting the ATP6AP1 C-tail could block Rheb activation and inhibit cancer cell proliferation and migration. Our findings highlight the versatility of PhastID in mapping transient PPIs in live cells, reveal ATP6AP1's role as an unconventional GEF for Rheb, and underscore the importance of ATP6AP1 in integrating mTORC1 activation signals through Rheb, filling in the missing link in Rheb/mTORC1 activation.
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Affiliation(s)
- Ran Feng
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, Guangzhou Key Laboratory of Healthy Aging Research, School of Life Sciences, Institute of Healthy Aging Research, Sun Yat-sen University, Guangzhou, Guangdong, China
- Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Feng Liu
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, Guangzhou Key Laboratory of Healthy Aging Research, School of Life Sciences, Institute of Healthy Aging Research, Sun Yat-sen University, Guangzhou, Guangdong, China.
| | - Ruofei Li
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, Guangzhou Key Laboratory of Healthy Aging Research, School of Life Sciences, Institute of Healthy Aging Research, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Zhifen Zhou
- Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Zhuoheng Lin
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, Guangzhou Key Laboratory of Healthy Aging Research, School of Life Sciences, Institute of Healthy Aging Research, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Song Lin
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, Guangzhou Key Laboratory of Healthy Aging Research, School of Life Sciences, Institute of Healthy Aging Research, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Shengcheng Deng
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, Guangzhou Key Laboratory of Healthy Aging Research, School of Life Sciences, Institute of Healthy Aging Research, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Yingying Li
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, Guangzhou Key Laboratory of Healthy Aging Research, School of Life Sciences, Institute of Healthy Aging Research, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Baoting Nong
- Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Ying Xia
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, Guangzhou Key Laboratory of Healthy Aging Research, School of Life Sciences, Institute of Healthy Aging Research, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Zhiyi Li
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, Guangzhou Key Laboratory of Healthy Aging Research, School of Life Sciences, Institute of Healthy Aging Research, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Xiaoqin Zhong
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, Guangzhou Key Laboratory of Healthy Aging Research, School of Life Sciences, Institute of Healthy Aging Research, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Shuhan Yang
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, Guangzhou Key Laboratory of Healthy Aging Research, School of Life Sciences, Institute of Healthy Aging Research, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Gang Wan
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, Guangzhou Key Laboratory of Healthy Aging Research, School of Life Sciences, Institute of Healthy Aging Research, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Wenbin Ma
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, Guangzhou Key Laboratory of Healthy Aging Research, School of Life Sciences, Institute of Healthy Aging Research, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Su Wu
- Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China.
| | - Zhou Songyang
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, Guangzhou Key Laboratory of Healthy Aging Research, School of Life Sciences, Institute of Healthy Aging Research, Sun Yat-sen University, Guangzhou, Guangdong, China.
- Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China.
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Yang L, Liao J, Huang H, Lee TL, Qi H. Stage-specific regulation of undifferentiated spermatogonia by AKT1S1-mediated AKT-mTORC1 signaling during mouse spermatogenesis. Dev Biol 2024; 509:11-27. [PMID: 38311163 DOI: 10.1016/j.ydbio.2024.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 11/03/2023] [Accepted: 02/01/2024] [Indexed: 02/10/2024]
Abstract
Undifferentiated spermatogonia are composed of a heterogeneous cell population including spermatogonial stem cells (SSCs). Molecular mechanisms underlying the regulation of various spermatogonial cohorts during their self-renewal and differentiation are largely unclear. Here we show that AKT1S1, an AKT substrate and inhibitor of mTORC1, regulates the homeostasis of undifferentiated spermatogonia. Although deletion of Akt1s1 in mouse appears not grossly affecting steady-state spermatogenesis and male mice are fertile, the subset of differentiation-primed OCT4+ spermatogonia decreased significantly, whereas self-renewing GFRα1+ and proliferating PLZF+ spermatogonia were sustained. Both neonatal prospermatogonia and the first wave spermatogenesis were greatly reduced in Akt1s1-/- mice. Further analyses suggest that OCT4+ spermatogonia in Akt1s1-/- mice possess altered PI3K/AKT-mTORC1 signaling, gene expression and carbohydrate metabolism, leading to their functionally compromised developmental potential. Collectively, these results revealed an important role of AKT1S1 in mediating the stage-specific signals that regulate the self-renewal and differentiation of spermatogonia during mouse spermatogenesis.
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Affiliation(s)
- Lele Yang
- Center for Cell Lineage and Development, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China; CAS Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China; Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China; GIBH-HKU Guangdong-Hong Kong Stem Cell and Regenerative Medicine Research Center, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China; GIBH-CUHK Joint Research Laboratory on Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China
| | - Jinyue Liao
- GIBH-CUHK Joint Research Laboratory on Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China; School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong
| | - Hongying Huang
- The Experimental Animal Center, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China
| | - Tin Lap Lee
- GIBH-CUHK Joint Research Laboratory on Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China; School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong
| | - Huayu Qi
- Center for Cell Lineage and Development, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China; CAS Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China; Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China; GIBH-HKU Guangdong-Hong Kong Stem Cell and Regenerative Medicine Research Center, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China; GIBH-CUHK Joint Research Laboratory on Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China.
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8
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Alghamdi M, Chen JF, Jungbluth A, Koutzaki S, Palmer MB, Al-Ahmadie HA, Fine SW, Gopalan A, Sarungbam J, Sirintrapun SJ, Tickoo SK, Reuter VE, Chen YB. L1 Cell Adhesion Molecule (L1CAM) Expression and Molecular Alterations Distinguish Low-Grade Oncocytic Tumor From Eosinophilic Chromophobe Renal Cell Carcinoma. Mod Pathol 2024; 37:100467. [PMID: 38460672 PMCID: PMC11102321 DOI: 10.1016/j.modpat.2024.100467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 02/06/2024] [Accepted: 03/01/2024] [Indexed: 03/11/2024]
Abstract
Renal low-grade oncocytic tumor (LOT) is a recently recognized renal cell neoplasm designated within the "other oncocytic tumors" category in the 2022 World Health Organization classification system. Although the clinicopathologic, immunohistochemical, and molecular features reported for LOT have been largely consistent, the data are relatively limited. The morphologic overlap between LOT and other low-grade oncocytic neoplasms, particularly eosinophilic chromophobe renal cell carcinoma (E-chRCC), remains a controversial area in renal tumor classification. To address this uncertainty, we characterized and compared large cohorts of LOT (n = 67) and E-chRCC (n = 69) and revealed notable differences between the 2 entities. Clinically, LOT predominantly affected women, whereas E-chRCC showed a male predilection. Histologically, although almost all LOTs were dominated by a small-nested pattern, E-chRCC mainly showed solid and tubular architectures. Molecular analysis revealed that 87% of LOT cases harbored mutations in the tuberous sclerosis complex (TSC)-mTOR complex 1 (mTORC1) pathway, most frequently in MTOR and RHEB genes; a subset of LOT cases had chromosomal 7 and 19q gains. In contrast, E-chRCC lacked mTORC1 mutations, and 60% of cases displayed chromosomal losses characteristic of chRCC. We also explored the cell of origin for LOT and identified L1 cell adhesion molecule (L1CAM), a collecting duct and connecting tubule principal cell marker, as a highly sensitive and specific ancillary test for differentiating LOT from E-chRCC. This distinctive L1CAM immunohistochemical labeling suggests the principal cells as the cell of origin for LOT, unlike the intercalated cell origin of E-chRCC and oncocytoma. The ultrastructural analysis of LOT showed normal-appearing mitochondria and intracytoplasmic lumina with microvilli, different from what has been described for chRCC. Our study further supports LOT as a unique entity with a benign clinical course. Based on the likely cell of origin and its clinicopathologic characteristics, we propose that changing the nomenclature of LOT to "Oncocytic Principal Cell Adenoma of the Kidney" may be a better way to define and describe this entity.
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Affiliation(s)
- Mohammed Alghamdi
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York; Department of Pathology and Laboratory Medicine, Hospital of the University of Pennsylvania, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Jie-Fu Chen
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Achim Jungbluth
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Sirma Koutzaki
- Department of Pathology and Laboratory Medicine, Hospital of the University of Pennsylvania, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Matthew B Palmer
- Department of Pathology and Laboratory Medicine, Hospital of the University of Pennsylvania, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Hikmat A Al-Ahmadie
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Samson W Fine
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Anuradha Gopalan
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Judy Sarungbam
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - S Joseph Sirintrapun
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Satish K Tickoo
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Victor E Reuter
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Ying-Bei Chen
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York.
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9
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Wang Y, Guo R, Piedras BI, Tang HY, Asara JM, Tempera I, Lieberman PM, Gewurz BE. The CTLH Ubiquitin Ligase Substrates ZMYND19 and MKLN1 Negatively Regulate mTORC1 at the Lysosomal Membrane. RESEARCH SQUARE 2024:rs.3.rs-4259395. [PMID: 38746323 PMCID: PMC11092817 DOI: 10.21203/rs.3.rs-4259395/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Most Epstein-Barr virus-associated gastric carcinoma (EBVaGC) harbor non-silent mutations that activate phosphoinositide 3 kinase (PI3K) to drive downstream metabolic signaling. To gain insights into PI3K/mTOR pathway dysregulation in this context, we performed a human genome-wide CRISPR/Cas9 screen for hits that synergistically blocked EBVaGC proliferation together with the PI3K antagonist alpelisib. Multiple subunits of carboxy terminal to LisH (CTLH) E3 ligase, including the catalytic MAEA subunit, were among top screen hits. CTLH negatively regulates gluconeogenesis in yeast, but not in higher organisms. Instead, we identified that the CTLH substrates MKLN1 and ZMYND19, which highly accumulated upon MAEA knockout, associated with one another and with lysosomes to inhibit mTORC1. ZMYND19/MKLN1 bound Raptor and RagA/C, but rather than perturbing mTORC1 lysosomal recruitment, instead blocked a late stage of its activation, independently of the tuberous sclerosis complex. Thus, CTLH enables cells to rapidly tune mTORC1 activity at the lysosomal membrane via the ubiquitin/proteasome pathway.
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Affiliation(s)
- Yin Wang
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, 181 Longwood Avenue, Boston, MA 02115, USA; Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - Rui Guo
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, 181 Longwood Avenue, Boston, MA 02115, USA; Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - Brenda Iturbide Piedras
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, 181 Longwood Avenue, Boston, MA 02115, USA; Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | | | - John M Asara
- Division of Signal Transduction, Beth Israel Deaconess Medical Center and Department of Medicine, Harvard Medical School, Boston, MA, USA
| | | | | | - Benjamin E Gewurz
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, 181 Longwood Avenue, Boston, MA 02115, USA; Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Program in Virology, Harvard Medical School
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10
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Davoody S, Asgari Taei A, Khodabakhsh P, Dargahi L. mTOR signaling and Alzheimer's disease: What we know and where we are? CNS Neurosci Ther 2024; 30:e14463. [PMID: 37721413 PMCID: PMC11017461 DOI: 10.1111/cns.14463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 08/28/2023] [Accepted: 08/29/2023] [Indexed: 09/19/2023] Open
Abstract
Despite the great body of research done on Alzheimer's disease, the underlying mechanisms have not been vividly investigated. To date, the accumulation of amyloid-beta plaques and tau tangles constitutes the hallmark of the disease; however, dysregulation of the mammalian target of rapamycin (mTOR) seems to be significantly involved in the pathogenesis of the disease as well. mTOR, as a serine-threonine protein kinase, was previously known for controlling many cellular functions such as cell size, autophagy, and metabolism. In this regard, mammalian target of rapamycin complex 1 (mTORC1) may leave anti-aging impacts by robustly inhibiting autophagy, a mechanism that inhibits the accumulation of damaged protein aggregate and dysfunctional organelles. Formation and aggregation of neurofibrillary tangles and amyloid-beta plaques seem to be significantly regulated by mTOR signaling. Understanding the underlying mechanisms and connection between mTOR signaling and AD may suggest conducting clinical trials assessing the efficacy of rapamycin, as an mTOR inhibitor drug, in managing AD or may help develop other medications. In this literature review, we aim to elaborate mTOR signaling network mainly in the brain, point to gaps of knowledge, and define how and in which ways mTOR signaling can be connected with AD pathogenesis and symptoms.
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Affiliation(s)
- Samin Davoody
- Student Research Committee, School of MedicineShahid Beheshti University of Medical SciencesTehranIran
| | - Afsaneh Asgari Taei
- Neuroscience Research CenterShahid Beheshti University of Medical SciencesTehranIran
| | - Pariya Khodabakhsh
- Department of NeurophysiologyInstitute of Physiology, Eberhard Karls University of TübingenTübingenGermany
| | - Leila Dargahi
- Neurobiology Research CenterShahid Beheshti University of Medical SciencesTehranIran
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11
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Allard C, Miralpeix C, López-Gambero AJ, Cota D. mTORC1 in energy expenditure: consequences for obesity. Nat Rev Endocrinol 2024; 20:239-251. [PMID: 38225400 DOI: 10.1038/s41574-023-00934-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/29/2023] [Indexed: 01/17/2024]
Abstract
In eukaryotic cells, the mammalian target of rapamycin complex 1 (sometimes referred to as the mechanistic target of rapamycin complex 1; mTORC1) orchestrates cellular metabolism in response to environmental energy availability. As a result, at the organismal level, mTORC1 signalling regulates the intake, storage and use of energy by acting as a hub for the actions of nutrients and hormones, such as leptin and insulin, in different cell types. It is therefore unsurprising that deregulated mTORC1 signalling is associated with obesity. Strategies that increase energy expenditure offer therapeutic promise for the treatment of obesity. Here we review current evidence illustrating the critical role of mTORC1 signalling in the regulation of energy expenditure and adaptive thermogenesis through its various effects in neuronal circuits, adipose tissue and skeletal muscle. Understanding how mTORC1 signalling in one organ and cell type affects responses in other organs and cell types could be key to developing better, safer treatments targeting this pathway in obesity.
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Affiliation(s)
- Camille Allard
- University of Bordeaux, INSERM, Neurocentre Magendie, Bordeaux, France
| | | | | | - Daniela Cota
- University of Bordeaux, INSERM, Neurocentre Magendie, Bordeaux, France.
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12
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Giri H, Biswas I, Rezaie AR. Thrombomodulin: a multifunctional receptor modulating the endothelial quiescence. J Thromb Haemost 2024; 22:905-914. [PMID: 38266676 PMCID: PMC10960680 DOI: 10.1016/j.jtha.2024.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 01/01/2024] [Accepted: 01/05/2024] [Indexed: 01/26/2024]
Abstract
Thrombomodulin (TM) is a type 1 receptor best known for its function as an anticoagulant cofactor for thrombin activation of protein C on the surface of vascular endothelial cells. In addition to its anticoagulant cofactor function, TM also regulates fibrinolysis, complement, and inflammatory pathways. TM is a multidomain receptor protein with a lectin-like domain at its N-terminus that has been shown to exhibit direct anti-inflammatory functions. This domain is followed by 6 epidermal growth factor-like domains that support the interaction of TM with thrombin. The interaction inhibits the procoagulant function of thrombin and enables the protease to regulate the anticoagulant and fibrinolytic pathways by activating protein C and thrombin-activatable fibrinolysis inhibitor. TM has a Thr/Ser-rich region immediately above the membrane surface that harbors chondroitin sulfate glycosaminoglycans, and this region is followed by a single-spanning transmembrane and a C-terminal cytoplasmic domain. The structure and physiological function of the extracellular domains of TM have been extensively studied, and numerous excellent review articles have been published. However, the physiological function of the cytoplasmic domain of TM has remained poorly understood. Recent data from our laboratory suggest that intracellular signaling by the cytoplasmic domain of TM plays key roles in maintaining quiescence by modulating phosphatase and tensin homolog signaling in endothelial cells. This article briefly reviews the structure and function of extracellular domains of TM and focuses on the mechanism and possible physiological importance of the cytoplasmic domain of TM in modulating phosphatase and tensin homolog signaling in endothelial cells.
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Affiliation(s)
- Hemant Giri
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
| | - Indranil Biswas
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
| | - Alireza R Rezaie
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA; Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA.
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13
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Panchal NK, Samdani P, Sengupta T, Prince SE. Computational Analysis of Non-synonymous SNPs in ATM Kinase: Structural Insights, Functional Implications, and Inhibitor Discovery. Mol Biotechnol 2024:10.1007/s12033-024-01120-x. [PMID: 38489015 DOI: 10.1007/s12033-024-01120-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 02/13/2024] [Indexed: 03/17/2024]
Abstract
Ataxia telangiectasia-mutated (ATM) protein kinase, a key player in cellular integrity regulation, is known for its role in DNA damage response. This study investigates the broader impact of ATM on cellular processes and potential clinical manifestations arising from mutations, aiming to expand our understanding of ATM's diverse functions beyond conventional roles. The research employs a comprehensive set of computational techniques for a thorough analysis of ATM mutations. The mutation data are curated from dbSNP and HuVarBase databases. A meticulous assessment is conducted, considering factors such as deleterious effects, protein stability, oncogenic potential, and biophysical characteristics of the identified mutations. Conservation analysis, utilizing diverse computational tools, provides insights into the evolutionary significance of these mutations. Molecular docking and dynamic simulation analyses are carried out for selected mutations, investigating their interactions with Y2080D, AZD0156, and quercetin inhibitors to gauge potential therapeutic implications. Among the 419 mutations scrutinized, five (V1913C, Y2080D, L2656P, C2770G, and C2930G) are identified as both disease causing and protein destabilizing. The study reveals the oncogenic potential of these mutations, supported by findings from the COSMIC database. Notably, Y2080D is associated with haematopoietic and lymphoid cancers, while C2770G shows a correlation with squamous cell carcinomas. Molecular docking and dynamic simulation analyses highlight strong binding affinities of quercetin for Y2080D and AZD0156 for C2770G, suggesting potential therapeutic options. In summary, this computational analysis provides a comprehensive understanding of ATM mutations, revealing their potential implications in cellular integrity and cancer development. The study underscores the significance of Y2080D and C2770G mutations, offering valuable insights for future precision medicine targeting-specific ATM. Despite informative computational analyses, a significant research gap exists, necessitating essential in vitro and in vivo studies to validate the predicted effects of ATM mutations on protein structure and function.
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Affiliation(s)
- Nagesh Kishan Panchal
- Department of Biotechnology, School of Biosciences and Technology, Vellore Institute of Technology, Vellore, 632 014, India
| | - Poorva Samdani
- Department of Biomedical Sciences, School of Biosciences and Technology, Vellore Institute of Technology, Vellore, India
| | - Tiasa Sengupta
- Department of Biomedical Sciences, School of Biosciences and Technology, Vellore Institute of Technology, Vellore, India
| | - Sabina Evan Prince
- Department of Biotechnology, School of Biosciences and Technology, Vellore Institute of Technology, Vellore, 632 014, India.
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14
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Zhang Y, Wen J, Lai R, Zhang J, Li K, Zhang Y, Liu A, Bai X. Rheb1 is required for limb growth through regulating chondrogenesis in growth plate. Cell Tissue Res 2024; 395:261-269. [PMID: 38253890 PMCID: PMC10904423 DOI: 10.1007/s00441-024-03861-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 01/04/2024] [Indexed: 01/24/2024]
Abstract
Ras homology enriched in the brain (Rheb) is well established as a critical regulator of cell proliferation and differentiation in response to growth factors and nutrients. However, the role of Rheb1 in limb development remains unknown. Here, we found that Rheb1 was dynamically expressed during the proliferation and differentiation of chondrocytes in the growth plate. Given that Prrx1+ limb-bud-like mesenchymal cells are the source of limb chondrocytes and are essential for endochondral ossification, we conditionally deleted Rheb1 using Prrx1-Cre and found a limb dwarfism in Prrx1-Cre; Rheb1fl/fl mice. Normalized to growth plate height, the conditional knockout (cKO) mice exhibited a significant decrease in column count of proliferative zones which was increased in hypertrophic zones resulting in decreased growth plate size, indicating abnormal endochondral ossification. Interestingly, although Rheb1 deletion profoundly inhibited the transcription factor Sox9 in limb cartilage; levels of runx2 and collagen type 2 were both increased. These novel findings highlight the essential role of Rheb1 in limb growth and indicate a complex regulation of Rheb1 in chondrocyte proliferation and differentiation.
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Affiliation(s)
- Yuwei Zhang
- School of Basic Medical Science, Southern Medical University, Guangzhou, Guangdong, 510515, People's Republic of China
| | - Jiaxin Wen
- School of Basic Medical Science, Southern Medical University, Guangzhou, Guangdong, 510515, People's Republic of China
| | - Ruijun Lai
- The Third Affiliated Hospital of Southern Medical University, Guangzhou, Guangdong, 510515, People's Republic of China
| | - Jiahuan Zhang
- Laboratory Medicine, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, 510000, People's Republic of China
| | - Kai Li
- The Third Affiliated Hospital of Southern Medical University, Guangzhou, Guangdong, 510515, People's Republic of China
| | - Yue Zhang
- School of Basic Medical Science, Southern Medical University, Guangzhou, Guangdong, 510515, People's Republic of China.
| | - Anling Liu
- School of Basic Medical Science, Southern Medical University, Guangzhou, Guangdong, 510515, People's Republic of China.
| | - Xiaochun Bai
- School of Basic Medical Science, Southern Medical University, Guangzhou, Guangdong, 510515, People's Republic of China.
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15
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Myburgh E, Geoghegan V, Alves-Ferreira EV, Nievas YR, Grewal JS, Brown E, McLuskey K, Mottram JC. TORC1 is an essential regulator of nutrient-controlled proliferation and differentiation in Leishmania. EMBO Rep 2024; 25:1075-1105. [PMID: 38396206 PMCID: PMC10933368 DOI: 10.1038/s44319-024-00084-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 01/19/2024] [Accepted: 01/25/2024] [Indexed: 02/25/2024] Open
Abstract
Leishmania parasites undergo differentiation between various proliferating and non-dividing forms to adapt to changing host environments. The mechanisms that link environmental cues with the parasite's developmental changes remain elusive. Here, we report that Leishmania TORC1 is a key environmental sensor for parasite proliferation and differentiation in the sand fly-stage promastigotes and for replication of mammalian-stage amastigotes. We show that Leishmania RPTOR1, interacts with TOR1 and LST8, and identify new parasite-specific proteins that interact in this complex. We investigate TORC1 function by conditional deletion of RPTOR1, where under nutrient-rich conditions RPTOR1 depletion results in decreased protein synthesis and growth, G1 cell cycle arrest and premature differentiation from proliferative promastigotes to non-dividing mammalian-infective metacyclic forms. These parasites are unable to respond to nutrients to differentiate into proliferative retroleptomonads, which are required for their blood-meal induced amplification in sand flies and enhanced mammalian infectivity. We additionally show that RPTOR1-/- metacyclic promastigotes develop into amastigotes but do not proliferate in the mammalian host to cause pathology. RPTOR1-dependent TORC1 functionality represents a critical mechanism for driving parasite growth and proliferation.
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Affiliation(s)
- Elmarie Myburgh
- York Biomedical Research Institute, Hull York Medical School, University of York, York, YO10 5DD, UK.
| | - Vincent Geoghegan
- York Biomedical Research Institute, Department of Biology, University of York, York, YO10 5DD, UK
| | - Eliza Vc Alves-Ferreira
- York Biomedical Research Institute, Department of Biology, University of York, York, YO10 5DD, UK
| | - Y Romina Nievas
- York Biomedical Research Institute, Department of Biology, University of York, York, YO10 5DD, UK
| | - Jaspreet S Grewal
- York Biomedical Research Institute, Department of Biology, University of York, York, YO10 5DD, UK
| | - Elaine Brown
- York Biomedical Research Institute, Department of Biology, University of York, York, YO10 5DD, UK
| | - Karen McLuskey
- Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Jeremy C Mottram
- York Biomedical Research Institute, Department of Biology, University of York, York, YO10 5DD, UK
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16
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Zhao L, Gao N, Peng X, Chen L, Meng T, Jiang C, Jin J, Zhang J, Duan Q, Tian H, Weng L, Wang X, Tan X, Li Y, Qin H, Yuan J, Ge X, Deng L, Wang P. TRAF4-Mediated LAMTOR1 Ubiquitination Promotes mTORC1 Activation and Inhibits the Inflammation-Induced Colorectal Cancer Progression. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2301164. [PMID: 38229144 DOI: 10.1002/advs.202301164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 11/28/2023] [Indexed: 01/18/2024]
Abstract
Mechanistic target of rapamycin complex 1 (mTORC1) is a conserved serine/threonine kinase that integrates various environmental signals to regulate cell growth and metabolism. mTORC1 activation requires tethering to lysosomes by the Ragulator-Rag complex. However, the dynamic regulation of the interaction between Ragulator and Rag guanosine triphosphatase (GTPase) remains unclear. In this study, that LAMTOR1, an essential component of Ragulator, is dynamically ubiquitinated depending on amino acid abundance is reported. It is found that the E3 ligase TRAF4 directly interacts with LAMTOR1 and catalyzes the K63-linked polyubiquitination of LAMTOR1 at K151. Ubiquitination of LAMTOR1 by TRAF4 promoted its binding to Rag GTPases and enhanced mTORC1 activation, K151R knock-in or TRAF4 knock-out blocks amino acid-induced mTORC1 activation and accelerates the development of inflammation-induced colon cancer. This study revealed that TRAF4-mediated LAMTOR1 ubiquitination is a regulatory mechanism for mTORC1 activation and provides a therapeutic target for diseases involving mTORC1 dysregulation.
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Affiliation(s)
- Linlin Zhao
- Tongji University Cancer Center, Shanghai Tenth People's Hospital, Shanghai Frontiers Science Center of Nanocatalytic Medicine, School of Medicine, Tongji University, Shanghai, 200092, P. R. China
| | - Ni Gao
- Tongji University Cancer Center, Shanghai Tenth People's Hospital, Shanghai Frontiers Science Center of Nanocatalytic Medicine, School of Medicine, Tongji University, Shanghai, 200092, P. R. China
| | - Xiaoping Peng
- Tongji University Cancer Center, Shanghai Tenth People's Hospital, Shanghai Frontiers Science Center of Nanocatalytic Medicine, School of Medicine, Tongji University, Shanghai, 200092, P. R. China
| | - Lei Chen
- Tongji University Cancer Center, Shanghai Tenth People's Hospital, Shanghai Frontiers Science Center of Nanocatalytic Medicine, School of Medicine, Tongji University, Shanghai, 200092, P. R. China
| | - Tong Meng
- Tongji University Cancer Center, Shanghai Tenth People's Hospital, Shanghai Frontiers Science Center of Nanocatalytic Medicine, School of Medicine, Tongji University, Shanghai, 200092, P. R. China
- Department of Orthopedics, Shanghai General Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, 200940, P. R. China
| | - Cong Jiang
- Tongji University Cancer Center, Shanghai Tenth People's Hospital, Shanghai Frontiers Science Center of Nanocatalytic Medicine, School of Medicine, Tongji University, Shanghai, 200092, P. R. China
| | - Jiali Jin
- Tongji University Cancer Center, Shanghai Tenth People's Hospital, Shanghai Frontiers Science Center of Nanocatalytic Medicine, School of Medicine, Tongji University, Shanghai, 200092, P. R. China
| | - Jiawen Zhang
- Tongji University Cancer Center, Shanghai Tenth People's Hospital, Shanghai Frontiers Science Center of Nanocatalytic Medicine, School of Medicine, Tongji University, Shanghai, 200092, P. R. China
| | - Qiuhui Duan
- Tongji University Cancer Center, Shanghai Tenth People's Hospital, Shanghai Frontiers Science Center of Nanocatalytic Medicine, School of Medicine, Tongji University, Shanghai, 200092, P. R. China
| | - Hongling Tian
- Tongji University Cancer Center, Shanghai Tenth People's Hospital, Shanghai Frontiers Science Center of Nanocatalytic Medicine, School of Medicine, Tongji University, Shanghai, 200092, P. R. China
| | - Linjun Weng
- Tongji University Cancer Center, Shanghai Tenth People's Hospital, Shanghai Frontiers Science Center of Nanocatalytic Medicine, School of Medicine, Tongji University, Shanghai, 200092, P. R. China
| | - Xinbo Wang
- Tongji University Cancer Center, Shanghai Tenth People's Hospital, Shanghai Frontiers Science Center of Nanocatalytic Medicine, School of Medicine, Tongji University, Shanghai, 200092, P. R. China
| | - Xiao Tan
- Tongji University Cancer Center, Shanghai Tenth People's Hospital, Shanghai Frontiers Science Center of Nanocatalytic Medicine, School of Medicine, Tongji University, Shanghai, 200092, P. R. China
| | - Yaxu Li
- Tongji University Cancer Center, Shanghai Tenth People's Hospital, Shanghai Frontiers Science Center of Nanocatalytic Medicine, School of Medicine, Tongji University, Shanghai, 200092, P. R. China
| | - Huanlong Qin
- Department of Gastrointestinal Surgery, Shanghai Tenth People's Hospital, Tongji University, Shanghai, 200092, P. R. China
- Research Institute of Intestinal Diseases, Tongji University School of Medicine, Shanghai, 200092, P. R. China
| | - Jian Yuan
- Department of Biochemistry and Molecular Biology, Tongji University School of Medicine, Shanghai, 200092, P. R. China
- Research Center for Translational Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, 200120, P. R. China
| | - Xin Ge
- Tongji University Cancer Center, Shanghai Tenth People's Hospital, Shanghai Frontiers Science Center of Nanocatalytic Medicine, School of Medicine, Tongji University, Shanghai, 200092, P. R. China
| | - Lu Deng
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, P. R. China
| | - Ping Wang
- Tongji University Cancer Center, Shanghai Tenth People's Hospital, Shanghai Frontiers Science Center of Nanocatalytic Medicine, School of Medicine, Tongji University, Shanghai, 200092, P. R. China
- Department of Biochemistry and Molecular Biology, Tongji University School of Medicine, Shanghai, 200092, P. R. China
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17
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Xia L, Nie T, Lu F, Huang L, Shi X, Ren D, Lu J, Li X, Xu T, Cui B, Wang Q, Gao G, Yang Q. Direct regulation of FNIP1 and FNIP2 by MEF2 sustains MTORC1 activation and tumor progression in pancreatic cancer. Autophagy 2024; 20:505-524. [PMID: 37772772 PMCID: PMC10936626 DOI: 10.1080/15548627.2023.2259735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 09/12/2023] [Indexed: 09/30/2023] Open
Abstract
MTOR (mechanistic target of rapamycin kinase) complex 1 (MTORC1) orchestrates diverse environmental signals to facilitate cell growth and is frequently activated in cancer. Translocation of MTORC1 from the cytosol to the lysosomal surface by the RRAG GTPases is the key step in MTORC1 activation. Here, we demonstrated that transcription factors MEF2A and MEF2D synergistically regulated MTORC1 activation via modulating its cyto-lysosome shutting. Mechanically, MEF2A and MEF2D controlled the transcription of FNIP1 and FNIP2, the components of the FLCN-FNIP1 or FNIP2 complex that acts as a RRAGC-RRAGD GTPase-activating element to promote the recruitment of MTORC1 to lysosome and its activation. Furthermore, we determined that the pro-oncogenic protein kinase SRC/c-Src directly phosphorylated MEF2D at three conserved tyrosine residues. The tyrosine phosphorylation enhanced MEF2D transcriptional activity and was indispensable for MTORC1 activation. Finally, both the protein and tyrosine phosphorylation levels of MEF2D are elevated in human pancreatic cancers, positively correlating with MTORC1 activity. Depletion of both MEF2A and MEF2D or expressing the unphosphorylatable MEF2D mutant suppressed tumor cell growth. Thus, our study revealed a transcriptional regulatory mechanism of MTORC1 that promoted cell anabolism and proliferation and uncovered its critical role in pancreatic cancer progression.Abbreviation: ACTB: actin beta; ChIP: chromatin immunoprecipitation; EGF: epidermal growth factor; EIF4EBP1: eukaryotic translation initiation factor 4E binding protein 1; FLCN: folliculin; FNIP1: folliculin interacting protein 1; FNIP2: folliculin interacting protein 2; GAP: GTPase activator protein; GEF: guanine nucleotide exchange factors; GTPase: guanosine triphosphatase; LAMP2: lysosomal associated membrane protein 2; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; MEF2: myocyte enhancer factor 2; MEF2A: myocyte enhancer factor 2A; MEF2D: myocyte enhancer factor 2D; MEF2D-3YF: Y131F, Y333F, Y337F mutant; MTOR: mechanistic target of rapamycin kinase; MTORC1: MTOR complex 1; NR4A1: nuclear receptor subfamily 4 group A member 1; RPTOR: regulatory associated protein of MTOR complex 1; RHEB: Ras homolog, mTORC1 binding; RPS6KB1: ribosomal protein S6 kinase B1; RRAG: Ras related GTP binding; RT-qPCR: real time-quantitative PCR; SRC: SRC proto-oncogene, non-receptor tyrosine kinase; TMEM192: transmembrane protein 192; WT: wild-type.
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Affiliation(s)
- Li Xia
- Department of Experimental Surgery, Tangdu Hospital, The Fourth Military Medical University, Xi’an, Shaanxi, China
- Department of Neurosurgery, Tangdu Hospital, The Fourth Military Medical University, Xi’an, Shaanxi, China
| | - Tiejian Nie
- Department of Experimental Surgery, Tangdu Hospital, The Fourth Military Medical University, Xi’an, Shaanxi, China
| | - Fangfang Lu
- Department of Experimental Surgery, Tangdu Hospital, The Fourth Military Medical University, Xi’an, Shaanxi, China
| | - Lu Huang
- Department of Anesthesiology, Tangdu Hospital, The Fourth Military Medical University, Xi’an, Shaanxi, China
| | - Xiaolong Shi
- Department of Experimental Surgery, Tangdu Hospital, The Fourth Military Medical University, Xi’an, Shaanxi, China
| | - Dongni Ren
- Department of Experimental Surgery, Tangdu Hospital, The Fourth Military Medical University, Xi’an, Shaanxi, China
| | - Jianjun Lu
- Department of Experimental Surgery, Tangdu Hospital, The Fourth Military Medical University, Xi’an, Shaanxi, China
| | - Xiaobin Li
- Department of Experimental Surgery, Tangdu Hospital, The Fourth Military Medical University, Xi’an, Shaanxi, China
| | - Tuo Xu
- Department of Experimental Surgery, Tangdu Hospital, The Fourth Military Medical University, Xi’an, Shaanxi, China
| | - Bozhou Cui
- Department of Experimental Surgery, Tangdu Hospital, The Fourth Military Medical University, Xi’an, Shaanxi, China
| | - Qing Wang
- Department of General Surgery, Tangdu Hospital, The Fourth Military Medical University, Xi’an, Shaanxi, China
| | - Guodong Gao
- Department of Neurosurgery, Tangdu Hospital, The Fourth Military Medical University, Xi’an, Shaanxi, China
| | - Qian Yang
- Department of Experimental Surgery, Tangdu Hospital, The Fourth Military Medical University, Xi’an, Shaanxi, China
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18
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Wang S, Han Y, Liu R, Hou M, Neumann D, Zhang J, Wang F, Li Y, Zhao X, Schianchi F, Dai C, Liu L, Nabben M, Glatz JF, Wu X, Lu X, Li X, Luiken JJ. Glycolysis-Mediated Activation of v-ATPase by Nicotinamide Mononucleotide Ameliorates Lipid-Induced Cardiomyopathy by Repressing the CD36-TLR4 Axis. Circ Res 2024; 134:505-525. [PMID: 38422177 PMCID: PMC10906217 DOI: 10.1161/circresaha.123.322910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Revised: 01/16/2024] [Accepted: 01/23/2024] [Indexed: 03/02/2024]
Abstract
BACKGROUND Chronic overconsumption of lipids followed by their excessive accumulation in the heart leads to cardiomyopathy. The cause of lipid-induced cardiomyopathy involves a pivotal role for the proton-pump vacuolar-type H+-ATPase (v-ATPase), which acidifies endosomes, and for lipid-transporter CD36, which is stored in acidified endosomes. During lipid overexposure, an increased influx of lipids into cardiomyocytes is sensed by v-ATPase, which then disassembles, causing endosomal de-acidification and expulsion of stored CD36 from the endosomes toward the sarcolemma. Once at the sarcolemma, CD36 not only increases lipid uptake but also interacts with inflammatory receptor TLR4 (Toll-like receptor 4), together resulting in lipid-induced insulin resistance, inflammation, fibrosis, and cardiac dysfunction. Strategies inducing v-ATPase reassembly, that is, to achieve CD36 reinternalization, may correct these maladaptive alterations. For this, we used NAD+ (nicotinamide adenine dinucleotide)-precursor nicotinamide mononucleotide (NMN), inducing v-ATPase reassembly by stimulating glycolytic enzymes to bind to v-ATPase. METHODS Rats/mice on cardiomyopathy-inducing high-fat diets were supplemented with NMN and for comparison with a cocktail of lysine/leucine/arginine (mTORC1 [mechanistic target of rapamycin complex 1]-mediated v-ATPase reassembly). We used the following methods: RNA sequencing, mRNA/protein expression analysis, immunofluorescence microscopy, (co)immunoprecipitation/proximity ligation assay (v-ATPase assembly), myocellular uptake of [3H]chloroquine (endosomal pH), and [14C]palmitate, targeted lipidomics, and echocardiography. To confirm the involvement of v-ATPase in the beneficial effects of both supplementations, mTORC1/v-ATPase inhibitors (rapamycin/bafilomycin A1) were administered. Additionally, 2 heart-specific v-ATPase-knockout mouse models (subunits V1G1/V0d2) were subjected to these measurements. Mechanisms were confirmed in pharmacologically/genetically manipulated cardiomyocyte models of lipid overload. RESULTS NMN successfully preserved endosomal acidification during myocardial lipid overload by maintaining v-ATPase activity and subsequently prevented CD36-mediated lipid accumulation, CD36-TLR4 interaction toward inflammation, fibrosis, cardiac dysfunction, and whole-body insulin resistance. Lipidomics revealed C18:1-enriched diacylglycerols as lipid class prominently increased by high-fat diet and subsequently reversed/preserved by lysine/leucine/arginine/NMN treatment. Studies with mTORC1/v-ATPase inhibitors and heart-specific v-ATPase-knockout mice further confirmed the pivotal roles of v-ATPase in these beneficial actions. CONCLUSION NMN preserves heart function during lipid overload by preventing v-ATPase disassembly.
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Affiliation(s)
- Shujin Wang
- Institute of Life Sciences, School of Basic Medicine, Chongqing Medical University, China (S.W., Y.H., R.L., M.H., J.Z., X.Z., X. Li)
- Department of Genetics and Cell Biology, Faculty of Health, Medicine and Life Sciences, Maastricht University, the Netherlands (S.W., F.W., F.S., M.N., J.F.C.G., J.J.F.P.L.)
| | - Yinying Han
- Institute of Life Sciences, School of Basic Medicine, Chongqing Medical University, China (S.W., Y.H., R.L., M.H., J.Z., X.Z., X. Li)
- Department of Infectious Disease, The First Affiliated Hospital of Anhui Medical University, Hefei, China (Y.H.)
| | - Ruimin Liu
- Institute of Life Sciences, School of Basic Medicine, Chongqing Medical University, China (S.W., Y.H., R.L., M.H., J.Z., X.Z., X. Li)
- Department of Ultrasound, Beijing Anzhen Hospital, Capital Medical University, China (R.L.)
| | - Mengqian Hou
- Institute of Life Sciences, School of Basic Medicine, Chongqing Medical University, China (S.W., Y.H., R.L., M.H., J.Z., X.Z., X. Li)
| | - Dietbert Neumann
- Department of Pathology (D.N.), Maastricht University Medical Center+, the Netherlands
| | - Jun Zhang
- Institute of Life Sciences, School of Basic Medicine, Chongqing Medical University, China (S.W., Y.H., R.L., M.H., J.Z., X.Z., X. Li)
| | - Fang Wang
- Department of Genetics and Cell Biology, Faculty of Health, Medicine and Life Sciences, Maastricht University, the Netherlands (S.W., F.W., F.S., M.N., J.F.C.G., J.J.F.P.L.)
| | - Yumeng Li
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, China (Y.L., X.W.)
| | - Xueya Zhao
- Institute of Life Sciences, School of Basic Medicine, Chongqing Medical University, China (S.W., Y.H., R.L., M.H., J.Z., X.Z., X. Li)
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, China (Y.L., X.W.)
| | - Francesco Schianchi
- Department of Genetics and Cell Biology, Faculty of Health, Medicine and Life Sciences, Maastricht University, the Netherlands (S.W., F.W., F.S., M.N., J.F.C.G., J.J.F.P.L.)
| | - Chao Dai
- CAS Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences (CAS), Changsha, China (C.D., X.W.)
| | - Lizhong Liu
- Department of Physiology, Shenzhen University Medical School, Shenzhen University, China (L.L.)
| | - Miranda Nabben
- Department of Genetics and Cell Biology, Faculty of Health, Medicine and Life Sciences, Maastricht University, the Netherlands (S.W., F.W., F.S., M.N., J.F.C.G., J.J.F.P.L.)
- Department of Clinical Genetics (M.N., J.F.C.G., J.J.F.P.L.), Maastricht University Medical Center+, the Netherlands
- Cardiovascular Research Institute Maastricht School for Cardiovascular Diseases, Maastricht, the Netherlands (M.N.)
| | - Jan F.C. Glatz
- Department of Genetics and Cell Biology, Faculty of Health, Medicine and Life Sciences, Maastricht University, the Netherlands (S.W., F.W., F.S., M.N., J.F.C.G., J.J.F.P.L.)
- Department of Clinical Genetics (M.N., J.F.C.G., J.J.F.P.L.), Maastricht University Medical Center+, the Netherlands
| | - Xin Wu
- CAS Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences (CAS), Changsha, China (C.D., X.W.)
| | - Xifeng Lu
- Clinical Research Center, First Affiliated Hospital of Shantou University Medical College, China (X. Lu)
| | - Xi Li
- Institute of Life Sciences, School of Basic Medicine, Chongqing Medical University, China (S.W., Y.H., R.L., M.H., J.Z., X.Z., X. Li)
| | - Joost J.F.P. Luiken
- Department of Genetics and Cell Biology, Faculty of Health, Medicine and Life Sciences, Maastricht University, the Netherlands (S.W., F.W., F.S., M.N., J.F.C.G., J.J.F.P.L.)
- Department of Clinical Genetics (M.N., J.F.C.G., J.J.F.P.L.), Maastricht University Medical Center+, the Netherlands
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19
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Pumar OYT, Zanotelli MR, Lin MCJ, Schmitt RR, Green KS, Rojas KS, Hwang IY, Cerione RA, Wilson KF. A multiprotein signaling complex sustains AKT and mTOR/S6K activity necessary for the survival of cancer cells undergoing stress. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.01.03.522657. [PMID: 36711811 PMCID: PMC9881951 DOI: 10.1101/2023.01.03.522657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Cancer cells encounter stresses during tumor progression and metastatic spread, however, how they survive these challenges is not fully understood. We now identify a mechanism for cancer cell survival through the discovery of a multiprotein signaling complex that includes the GTPase Cdc42, the Cdc42 GEF/effector protein Dock7, AKT, mTOR and the mTORC1 regulatory partners TSC1, TSC2, and Rheb. This pro-survival signaling complex sustains the activated state of AKT by preventing its dephosphorylation at Ser473 during serum starvation, resulting in a low but critical activation of a Raptor-independent mTOR/S6K activity. We demonstrate that the Dock7 DHR1 domain, previously of unknown function, is responsible for preserving AKT phosphorylation through an interaction requiring its C2-like motif. Collectively, these findings help address long-standing questions of how Cdc42 signals mTOR activation by elucidating the unique functions of its signaling partner Dock7 as an AKT regulator necessary for resistance to anoikis and apoptosis in cancer cells.
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Affiliation(s)
| | | | - Miao-chong Joy Lin
- Department of Molecular Medicine, Cornell University, Ithaca, NY 14853, USA
| | - Rebecca R. Schmitt
- Department of Molecular Medicine, Cornell University, Ithaca, NY 14853, USA
| | - Kai Su Green
- Department of Molecular Medicine, Cornell University, Ithaca, NY 14853, USA
| | - Katherine S. Rojas
- Department of Molecular Medicine, Cornell University, Ithaca, NY 14853, USA
| | - Irene Y. Hwang
- Department of Molecular Medicine, Cornell University, Ithaca, NY 14853, USA
| | - Richard A. Cerione
- Department of Molecular Medicine, Cornell University, Ithaca, NY 14853, USA
- Department of Chemistry, Cornell University, Ithaca, NY 14853, USA
| | - Kristin F. Wilson
- Department of Molecular Medicine, Cornell University, Ithaca, NY 14853, USA
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20
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Jhanwar-Uniyal M, Zeller SL, Spirollari E, Das M, Hanft SJ, Gandhi CD. Discrete Mechanistic Target of Rapamycin Signaling Pathways, Stem Cells, and Therapeutic Targets. Cells 2024; 13:409. [PMID: 38474373 DOI: 10.3390/cells13050409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 02/14/2024] [Accepted: 02/22/2024] [Indexed: 03/14/2024] Open
Abstract
The mechanistic target of rapamycin (mTOR) is a serine/threonine kinase that functions via its discrete binding partners to form two multiprotein complexes, mTOR complex 1 and 2 (mTORC1 and mTORC2). Rapamycin-sensitive mTORC1, which regulates protein synthesis and cell growth, is tightly controlled by PI3K/Akt and is nutrient-/growth factor-sensitive. In the brain, mTORC1 is also sensitive to neurotransmitter signaling. mTORC2, which is modulated by growth factor signaling, is associated with ribosomes and is insensitive to rapamycin. mTOR regulates stem cell and cancer stem cell characteristics. Aberrant Akt/mTOR activation is involved in multistep tumorigenesis in a variety of cancers, thereby suggesting that the inhibition of mTOR may have therapeutic potential. Rapamycin and its analogues, known as rapalogues, suppress mTOR activity through an allosteric mechanism that only suppresses mTORC1, albeit incompletely. ATP-catalytic binding site inhibitors are designed to inhibit both complexes. This review describes the regulation of mTOR and the targeting of its complexes in the treatment of cancers, such as glioblastoma, and their stem cells.
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Affiliation(s)
- Meena Jhanwar-Uniyal
- Department of Neurosurgery, Westchester Medical Center, New York Medical College, Valhalla, NY 10595, USA
| | - Sabrina L Zeller
- Department of Neurosurgery, Westchester Medical Center, New York Medical College, Valhalla, NY 10595, USA
| | - Eris Spirollari
- Department of Neurosurgery, Westchester Medical Center, New York Medical College, Valhalla, NY 10595, USA
| | - Mohan Das
- Department of Neurosurgery, Westchester Medical Center, New York Medical College, Valhalla, NY 10595, USA
| | - Simon J Hanft
- Department of Neurosurgery, Westchester Medical Center, New York Medical College, Valhalla, NY 10595, USA
| | - Chirag D Gandhi
- Department of Neurosurgery, Westchester Medical Center, New York Medical College, Valhalla, NY 10595, USA
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21
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Miller MJ, Akter D, Mahmud J, Chan GC. Human cytomegalovirus modulates mTORC1 to redirect mRNA translation within quiescently infected monocytes. J Virol 2024; 98:e0188823. [PMID: 38289104 PMCID: PMC10878035 DOI: 10.1128/jvi.01888-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 12/22/2023] [Indexed: 02/21/2024] Open
Abstract
Human cytomegalovirus (HCMV) utilizes peripheral blood monocytes as a means to systemically disseminate throughout the host. Following viral entry, HCMV stimulates non-canonical Akt signaling leading to the activation of mTORC1 and the subsequent translation of select antiapoptotic proteins within infected monocytes. However, the full extent to which the HCMV-initiated Akt/mTORC1 signaling axis reshapes the monocyte translatome is unclear. We found HCMV entry alone was able to stimulate widescale changes to mRNA translation levels and that inhibition of mTOR, a component of mTORC1, dramatically attenuated HCMV-induced protein synthesis. Although monocytes treated with normal myeloid growth factors also exhibited increased levels of translation, mTOR inhibition had no effect, suggesting HCMV activation of mTOR stimulates the acquisition of a unique translatome within infected monocytes. Indeed, polyribosomal profiling of HCMV-infected monocytes identified distinct prosurvival transcripts that were preferentially loaded with ribosomes when compared to growth factor-treated cells. Sirtuin 1 (SIRT1), a deacetylase that exerts prosurvival effects through regulation of the PI3K/Akt pathway, was found to be highly enriched following HCMV infection in an mTOR-dependent manner. Importantly, SIRT1 inhibition led to the death of HCMV-infected monocytes while having minimal effect on uninfected cells. SIRT1 also supported a positive feedback loop to sustain Akt/mTORC1 signaling following viral entry. Taken together, HCMV profoundly reshapes mRNA translation in an mTOR-dependent manner to enhance the synthesis of select factors necessary for the survival of infected monocytes.IMPORTANCEHuman cytomegalovirus (HCMV) infection is a significant cause of morbidity and mortality among the immunonaïve and immunocompromised. Peripheral blood monocytes are a major cell type responsible for disseminating the virus from the initial site of infection. In order for monocytes to mediate viral spread within the host, HCMV must subvert the naturally short lifespan of these cells. In this study, we performed polysomal profiling analysis, which demonstrated HCMV to globally redirect mRNA translation toward the synthesis of cellular prosurvival factors within infected monocytes. Specifically, HCMV entry into monocytes induced the translation of cellular SIRT1 to generate an antiapoptotic state. Defining the precise mechanisms through which HCMV stimulates survival will provide insight into novel anti-HCMV drugs able to target infected monocytes.
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Affiliation(s)
- Michael J. Miller
- Department of Microbiology and Immunology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Dilruba Akter
- Department of Microbiology and Immunology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Jamil Mahmud
- Department of Microbiology and Immunology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Gary C. Chan
- Department of Microbiology and Immunology, SUNY Upstate Medical University, Syracuse, New York, USA
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22
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Kamada Y, Umeda C, Mukai Y, Ohtsuka H, Otsubo Y, Yamashita A, Kosugi T. Structure-based engineering of Tor complexes reveals that two types of yeast TORC1 produce distinct phenotypes. J Cell Sci 2024; 137:jcs261625. [PMID: 38415789 PMCID: PMC10941655 DOI: 10.1242/jcs.261625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 01/18/2024] [Indexed: 02/29/2024] Open
Abstract
Certain proteins assemble into diverse complex states, each having a distinct and unique function in the cell. Target of rapamycin (Tor) complex 1 (TORC1) plays a central role in signalling pathways that allow cells to respond to the environment, including nutritional status signalling. TORC1 is widely recognised for its association with various diseases. The budding yeast Saccharomyces cerevisiae has two types of TORC1, Tor1-containing TORC1 and Tor2-containing TORC1, which comprise different constituent proteins but are considered to have the same function. Here, we computationally modelled the relevant complex structures and then, based on the structures, rationally engineered a Tor2 mutant that could form Tor complex 2 (TORC2) but not TORC1, resulting in a redesign of the complex states. Functional analysis of the Tor2 mutant revealed that the two types of TORC1 induce different phenotypes, with changes observed in rapamycin, caffeine and pH dependencies of cell growth, as well as in replicative and chronological lifespan. These findings uncovered by a general approach with huge potential - model structure-based engineering - are expected to provide further insights into various fields such as molecular evolution and lifespan.
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Affiliation(s)
- Yoshiaki Kamada
- Interdisciplinary Research Unit, National Institute for Basic Biology (NIBB), National Institutes of Natural Sciences (NINS), Okazaki, Aichi, 444-8585, Japan
- Basic Biology Program, SOKENDAI (The Graduate University for Advanced Studies), Hayama, Kanagawa, 240-0193, Japan
| | - Chiharu Umeda
- Department of Frontier Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga, 526-0829, Japan
| | - Yukio Mukai
- Department of Frontier Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga, 526-0829, Japan
| | - Hokuto Ohtsuka
- Laboratory of Molecular Microbiology, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Aichi, 464-8601, Japan
| | - Yoko Otsubo
- Interdisciplinary Research Unit, National Institute for Basic Biology (NIBB), National Institutes of Natural Sciences (NINS), Okazaki, Aichi, 444-8585, Japan
| | - Akira Yamashita
- Interdisciplinary Research Unit, National Institute for Basic Biology (NIBB), National Institutes of Natural Sciences (NINS), Okazaki, Aichi, 444-8585, Japan
| | - Takahiro Kosugi
- Research Center of Integrative Molecular Systems (CIMoS), Institute for Molecular Science (IMS), National Institutes of Natural Sciences (NINS), Okazaki, Aichi, 444-8585, Japan
- Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences (NINS), Okazaki, Aichi, 444-8585, Japan
- Molecular Science Program, SOKENDAI (The Graduate University for Advanced Studies), Hayama, Kanagawa, 240-0193, Japan
- Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency, Kawaguchi, Saitama, 332-0012, Japan
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23
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Joshi JN, Lerner AD, Scallo F, Grumet AN, Matteson P, Millonig JH, Valvezan AJ. mTORC1 activity oscillates throughout the cell cycle promoting mitotic entry and differentially influencing autophagy induction. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.06.579216. [PMID: 38370755 PMCID: PMC10871213 DOI: 10.1101/2024.02.06.579216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
Mechanistic Target of Rapamycin Complex 1 (mTORC1) is a master metabolic regulator that stimulates anabolic cell growth while suppressing catabolic processes such as autophagy. mTORC1 is active in most, if not all, proliferating eukaryotic cells. However, it remains unclear whether and how mTORC1 activity changes from one cell cycle phase to another. Here we tracked mTORC1 activity through the complete cell cycle and uncover oscillations in its activity. We find that mTORC1 activity peaks in S and G2, and is lowest in mitosis and G1. We further demonstrate that multiple mechanisms are involved in controlling this oscillation. The interphase oscillation is mediated through the TSC complex, an upstream negative regulator of mTORC1, but is independent of major known regulatory inputs to the TSC complex, including Akt, Mek/Erk, and CDK4/6 signaling. By contrast, suppression of mTORC1 activity in mitosis does not require the TSC complex, and instead involves CDK1-dependent control of the subcellular localization of mTORC1 itself. Functionally, we find that in addition to its well-established role in promoting progression through G1, mTORC1 also promotes progression through S and G2, and is important for satisfying the Wee1- and Chk1- dependent G2/M checkpoint to allow entry into mitosis. We also find that low mTORC1 activity in G1 sensitizes cells to autophagy induction in response to partial mTORC1 inhibition or reduced nutrient levels. Together these findings demonstrate that mTORC1 is differentially regulated throughout the cell cycle, with important phase-specific functional consequences in proliferating cells.
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Affiliation(s)
- Jay N. Joshi
- Molecular Biosciences Program, Rutgers University, Piscataway, NJ, USA
- Center for Advanced Biotechnology and Medicine, Piscataway, NJ, USA
| | - Ariel D. Lerner
- Center for Advanced Biotechnology and Medicine, Piscataway, NJ, USA
| | - Frank Scallo
- Center for Advanced Biotechnology and Medicine, Piscataway, NJ, USA
- Present affiliation: Yale School of Medicine, New Haven, CT, USA
| | | | - Paul Matteson
- Center for Advanced Biotechnology and Medicine, Piscataway, NJ, USA
| | - James H. Millonig
- Center for Advanced Biotechnology and Medicine, Piscataway, NJ, USA
- Department of Neuroscience and Cell Biology, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ, USA
| | - Alexander J. Valvezan
- Center for Advanced Biotechnology and Medicine, Piscataway, NJ, USA
- Department of Pharmacology, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ, USA
- Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA
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24
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Bagh MB, Appu AP, Sadhukhan T, Mondal A, Plavelil N, Raghavankutty M, Supran AM, Sadhukhan S, Liu A, Mukherjee AB. Disruption of lysosomal nutrient sensing scaffold contributes to pathogenesis of a fatal neurodegenerative lysosomal storage disease. J Biol Chem 2024; 300:105641. [PMID: 38211816 PMCID: PMC10862020 DOI: 10.1016/j.jbc.2024.105641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 11/27/2023] [Accepted: 12/17/2023] [Indexed: 01/13/2024] Open
Abstract
The ceroid lipofuscinosis neuronal 1 (CLN1) disease, formerly called infantile neuronal ceroid lipofuscinosis, is a fatal hereditary neurodegenerative lysosomal storage disorder. This disease is caused by loss-of-function mutations in the CLN1 gene, encoding palmitoyl-protein thioesterase-1 (PPT1). PPT1 catalyzes depalmitoylation of S-palmitoylated proteins for degradation and clearance by lysosomal hydrolases. Numerous proteins, especially in the brain, require dynamic S-palmitoylation (palmitoylation-depalmitoylation cycles) for endosomal trafficking to their destination. While 23 palmitoyl-acyl transferases in the mammalian genome catalyze S-palmitoylation, depalmitoylation is catalyzed by thioesterases such as PPT1. Despite these discoveries, the pathogenic mechanism of CLN1 disease has remained elusive. Here, we report that in the brain of Cln1-/- mice, which mimic CLN1 disease, the mechanistic target of rapamycin complex-1 (mTORC1) kinase is hyperactivated. The activation of mTORC1 by nutrients requires its anchorage to lysosomal limiting membrane by Rag GTPases and Ragulator complex. These proteins form the lysosomal nutrient sensing scaffold to which mTORC1 must attach to activate. We found that in Cln1-/- mice, two constituent proteins of the Ragulator complex (vacuolar (H+)-ATPase and Lamtor1) require dynamic S-palmitoylation for endosomal trafficking to the lysosomal limiting membrane. Intriguingly, Ppt1 deficiency in Cln1-/- mice misrouted these proteins to the plasma membrane disrupting the lysosomal nutrient sensing scaffold. Despite this defect, mTORC1 was hyperactivated via the IGF1/PI3K/Akt-signaling pathway, which suppressed autophagy contributing to neuropathology. Importantly, pharmacological inhibition of PI3K/Akt suppressed mTORC1 activation, restored autophagy, and ameliorated neurodegeneration in Cln1-/- mice. Our findings reveal a previously unrecognized role of Cln1/Ppt1 in regulating mTORC1 activation and suggest that IGF1/PI3K/Akt may be a targetable pathway for CLN1 disease.
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Affiliation(s)
- Maria B Bagh
- Section on Developmental Genetics, Division of Translational Medicine, Eunice Kennedy-Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Abhilash P Appu
- Section on Developmental Genetics, Division of Translational Medicine, Eunice Kennedy-Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Tamal Sadhukhan
- Section on Developmental Genetics, Division of Translational Medicine, Eunice Kennedy-Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Avisek Mondal
- Section on Developmental Genetics, Division of Translational Medicine, Eunice Kennedy-Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Nisha Plavelil
- Section on Developmental Genetics, Division of Translational Medicine, Eunice Kennedy-Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Mahadevan Raghavankutty
- Section on Developmental Genetics, Division of Translational Medicine, Eunice Kennedy-Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Ajayan M Supran
- Section on Developmental Genetics, Division of Translational Medicine, Eunice Kennedy-Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Sriparna Sadhukhan
- Section on Developmental Genetics, Division of Translational Medicine, Eunice Kennedy-Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Aiyi Liu
- Biostatistics and Bioinformatics Branch (HNT72), Eunice Kennedy-Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Anil B Mukherjee
- Section on Developmental Genetics, Division of Translational Medicine, Eunice Kennedy-Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA.
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25
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Kincheloe GN, Roberson PA, Jefferson LS, Kimball SR. Tissue-specific expression differences in Ras-related GTP-binding proteins in male rats. Physiol Rep 2024; 12:e15928. [PMID: 38296461 PMCID: PMC10830385 DOI: 10.14814/phy2.15928] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 12/30/2023] [Accepted: 01/14/2024] [Indexed: 02/05/2024] Open
Abstract
The protein kinase Mechanistic Target of Rapamycin (mTOR) in Complex 1 (mTORC1) is regulated in part by the Ras-related GTP-binding proteins (Rag GTPases). Rag GTPases form a heterodimeric complex consisting of either RagA or RagB associated with either RagC or RagD and act to localize mTORC1 to the lysosomal membrane. Until recently, RagA and RagB were thought to be functionally redundant, as were RagC and RagD. However, recent research suggests that the various isoforms differentially activate mTORC1. Here, the mRNA expression and protein abundance of the Rag GTPases was compared across male rat skeletal muscle, heart, liver, kidney, and brain. Whereas mRNA expression of RagA was higher than RagB in nearly all tissues studied, RagB protein abundance was higher than RagA in all tissues besides skeletal muscle. RagC mRNA expression was more abundant or equal to RagD mRNA, and RagD protein was more abundant than RagC protein in all tissues. Moreover, the proportion of RagB in the short isoform was greater than the long in liver, whereas the opposite was true in brain. These results serve to further elucidate Rag GTPase expression and offer potential explanations for the differential responses to amino acids that are observed in different tissues.
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Affiliation(s)
- Gregory N. Kincheloe
- Department of Cellular and Molecular PhysiologyPenn State College of MedicineHersheyPennsylvaniaUSA
- Present address:
Department of AnatomyUCSF College of MedicineSan FranciscoCaliforniaUSA
| | - Paul A. Roberson
- Department of Cellular and Molecular PhysiologyPenn State College of MedicineHersheyPennsylvaniaUSA
- Present address:
Division of Endocrinology, Metabolism, Diabetes, Department of MedicineUniversity of Colorado – Anschutz Medical CampusAuroraColoradoUSA
| | - Leonard S. Jefferson
- Department of Cellular and Molecular PhysiologyPenn State College of MedicineHersheyPennsylvaniaUSA
| | - Scot R. Kimball
- Department of Cellular and Molecular PhysiologyPenn State College of MedicineHersheyPennsylvaniaUSA
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Nikolic M, Jeremic N, Lazarevic N, Stojanovic A, Milojevic Samanovic A, Novakovic J, Zivkovic V, Nikolic M, Nedeljkovic N, Mitrovic S, Jakovljevic V. Sacubitril/valsartan promotes white adipose tissue browning in rats with metabolic syndrome through activation of mTORC1. Biofactors 2024. [PMID: 38284316 DOI: 10.1002/biof.2040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 01/06/2024] [Indexed: 01/30/2024]
Abstract
In addition to their usual use in the treatment of cardiovascular disease, weak evidence is available for the potential of combined use of neprilysin inhibitor (sacubitril) and AT1 receptor antagonist (valsartan) to promote browning of white adipose tissue (WAT) in rats with metabolic syndrome (MetS). This study involved 32 male Wistar albino rats divided into four groups: CTRL-healthy control rats; ENT-healthy rats treated with sacubitril/valsartan; MS-rats with MetS; MS + ENT-rats with MetS treated with sacubitril/valsartan. After finishing the experimental protocol, different WAT depots were isolated for further analysis of molecular pathways. Molecular docking and molecular dynamics studies were used for in silico assessment of the binding affinity of sacubitril and valsartan towards subunits of mechanistic target of rapamycin complex 1 (mTORC1). Sacubitril/valsartan treatment markedly diminished morphological changes in adipose tissue, resulting in smaller lipid size and multilocular lipid droplet structure in WAT. We showed significantly higher protein expression of uncoupling protein-1 (UCP-1) and mTORC1 in WAT of MS + ENT rats, correlating with increased relative gene expression of browning-related markers in tissue of rats treated with sacubitril/valsartan compared with MS group of rats. In silico analysis showed that sacubitrilat and valsartan exhibited the highest binding affinity against mTOR and mLST8, forming stable complexes with these mTORC1 subunits. The observed results confirmed strong potential of combined sacubitril/valsartan treatment to increase browning markers expression in different WAT depots in MetS condition and to form permanent complexes with mTOR and mLST8 subunits over the time.
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Affiliation(s)
- Marina Nikolic
- Department of Physiology, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
- Center of Excellence for Redox Balance Research in Cardiovascular and Metabolic Disorders, Kragujevac, Serbia
| | - Nevena Jeremic
- Center of Excellence for Redox Balance Research in Cardiovascular and Metabolic Disorders, Kragujevac, Serbia
- Department of Pharmacy, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
- Federal State Autonomous Educational Institution of Higher Education I.M. Sechenov First Moscow State Medical University of the Ministry of Health of the Russian Federation (Sechenov University), Moscow, Russia
| | - Nevena Lazarevic
- Center of Excellence for Redox Balance Research in Cardiovascular and Metabolic Disorders, Kragujevac, Serbia
- Department of Pharmacy, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
- Department of Human Pathology, 1st Moscow State Medical, University IM Sechenov, Moscow, Russia
| | - Aleksandra Stojanovic
- Center of Excellence for Redox Balance Research in Cardiovascular and Metabolic Disorders, Kragujevac, Serbia
- Department of Pharmacy, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
| | - Andjela Milojevic Samanovic
- Center of Excellence for Redox Balance Research in Cardiovascular and Metabolic Disorders, Kragujevac, Serbia
- Department of Dentistry, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
| | - Jovana Novakovic
- Center of Excellence for Redox Balance Research in Cardiovascular and Metabolic Disorders, Kragujevac, Serbia
- Department of Pharmacy, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
| | - Vladimir Zivkovic
- Department of Physiology, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
- Center of Excellence for Redox Balance Research in Cardiovascular and Metabolic Disorders, Kragujevac, Serbia
- Department of Pharmacology, I.M. Sechenov First Moscow State Medical University, Moscow, Russia
| | - Milos Nikolic
- Department of Pharmacy, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
| | - Nikola Nedeljkovic
- Department of Pharmacy, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
| | - Slobodanka Mitrovic
- Department of Pathology, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
| | - Vladimir Jakovljevic
- Department of Physiology, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
- Center of Excellence for Redox Balance Research in Cardiovascular and Metabolic Disorders, Kragujevac, Serbia
- Department of Human Pathology, 1st Moscow State Medical, University IM Sechenov, Moscow, Russia
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Morozumi Y, Mahayot F, Nakase Y, Soong JX, Yamawaki S, Sofyantoro F, Imabata Y, Oda AH, Tamura M, Kofuji S, Akikusa Y, Shibatani A, Ohta K, Shiozaki K. Rapamycin-sensitive mechanisms confine the growth of fission yeast below the temperatures detrimental to cell physiology. iScience 2024; 27:108777. [PMID: 38269097 PMCID: PMC10805665 DOI: 10.1016/j.isci.2023.108777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 10/12/2023] [Accepted: 12/22/2023] [Indexed: 01/26/2024] Open
Abstract
Cells cease to proliferate above their growth-permissible temperatures, a ubiquitous phenomenon generally attributed to heat damage to cellular macromolecules. We here report that, in the presence of rapamycin, a potent inhibitor of Target of Rapamycin Complex 1 (TORC1), the fission yeast Schizosaccharomyces pombe can proliferate at high temperatures that usually arrest its growth. Consistently, mutations to the TORC1 subunit RAPTOR/Mip1 and the TORC1 substrate Sck1 significantly improve cellular heat resistance, suggesting that TORC1 restricts fission yeast growth at high temperatures. Aiming for a more comprehensive understanding of the negative regulation of high-temperature growth, we conducted genome-wide screens, which identified additional factors that suppress cell proliferation at high temperatures. Among them is Mks1, which is phosphorylated in a TORC1-dependent manner, forms a complex with the 14-3-3 protein Rad24, and suppresses the high-temperature growth independently of Sck1. Our study has uncovered unexpected mechanisms of growth restraint even below the temperatures deleterious to cell physiology.
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Affiliation(s)
- Yuichi Morozumi
- Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Fontip Mahayot
- Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Yukiko Nakase
- Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Jia Xin Soong
- Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Sayaka Yamawaki
- Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Fajar Sofyantoro
- Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
- Faculty of Biology, Universitas Gadjah Mada, Sleman, Yogyakarta 55281, Indonesia
| | - Yuki Imabata
- Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Arisa H. Oda
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Meguro-ku, Tokyo 153-8902, Japan
| | - Miki Tamura
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Meguro-ku, Tokyo 153-8902, Japan
| | - Shunsuke Kofuji
- Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Yutaka Akikusa
- Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Ayu Shibatani
- Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Kunihiro Ohta
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Meguro-ku, Tokyo 153-8902, Japan
| | - Kazuhiro Shiozaki
- Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA 95616, USA
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Liu Y, Zhang M, Jang H, Nussinov R. The allosteric mechanism of mTOR activation can inform bitopic inhibitor optimization. Chem Sci 2024; 15:1003-1017. [PMID: 38239681 PMCID: PMC10793652 DOI: 10.1039/d3sc04690g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 12/06/2023] [Indexed: 01/22/2024] Open
Abstract
mTOR serine/threonine kinase is a cornerstone in the PI3K/AKT/mTOR pathway. Yet, the detailed mechanism of activation of its catalytic core is still unresolved, likely due to mTOR complexes' complexity. Its dysregulation was implicated in cancer and neurodevelopmental disorders. Using extensive molecular dynamics (MD) simulations and compiled published experimental data, we determine exactly how mTOR's inherent motifs can control the conformational changes in the kinase domain, thus kinase activity. We also chronicle the critical regulation by the unstructured negative regulator domain (NRD). When positioned inside the catalytic cleft (NRD IN state), mTOR tends to adopt a deep and closed catalytic cleft. This is primarily due to the direct interaction with the FKBP-rapamycin binding (FRB) domain which restricts it, preventing substrate access. Conversely, when outside the catalytic cleft (NRD OUT state), mTOR favors an open conformation, exposing the substrate-binding site on the FRB domain. We further show how an oncogenic mutation (L2427R) promotes shifting the mTOR ensemble toward the catalysis-favored state. Collectively, we extend mTOR's "active-site restriction" mechanism and clarify mutation action. In particular, our mechanism suggests that RMC-5552 (RMC-6272) bitopic inhibitors may benefit from adjustment of the (PEG8) linker length when targeting certain mTOR variants. In the cryo-EM mTOR/RMC-5552 structure, the distance between the allosteric and orthosteric inhibitors is ∼22.7 Å. With a closed catalytic cleft, this linker bridges the sites. However, in our activation mechanism, in the open cleft it expands to ∼24.7 Å, offering what we believe to be the first direct example of how discovering an activation mechanism can potentially increase the affinity of inhibitors targeting mutants.
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Affiliation(s)
- Yonglan Liu
- Cancer Innovation Laboratory, National Cancer Institute Frederick MD 21702 USA
| | - Mingzhen Zhang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research Frederick MD 21702 USA +1-301-846-5579
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research Frederick MD 21702 USA +1-301-846-5579
| | - Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research Frederick MD 21702 USA +1-301-846-5579
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University Tel Aviv 69978 Israel
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29
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Li J, Yang D, Lin Y, Xu W, Zhao SM, Wang C. OTUD3 suppresses the mTORC1 signaling by deubiquitinating KPTN. Front Pharmacol 2024; 14:1337732. [PMID: 38288086 PMCID: PMC10822905 DOI: 10.3389/fphar.2023.1337732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 12/27/2023] [Indexed: 01/31/2024] Open
Abstract
Background: Ubiquitination and deubiquitination modifications play pivotal roles in eukaryotic life processes, regulating protein dynamics via the ubiquitin-proteasome pathway. Dysregulation can impact disease development, including cancer and neurodegenerative disorders. Increasing evidence highlights their role in tumorigenesis, modulating key proteins. OTUD3, a deubiquitinase, stabilizes PTEN, suppressing tumor growth by inhibiting PI3K-AKT signaling. Yet, further OTUD3 substrates remain underexplored. Methods: We employed the In vivo ubiquitination assay to investigate the ubiquitination role of OTUD3 on KPTN within the cellular context. Additionally, CRISPR/Cas9 editing and Immunofluorescence were utilized to study the impact of OTUD3 on the mTOR signaling pathway in cells. Furthermore, Cell proliferation assay and NMR were employed to explore the effects of OTUD3 on cellular growth and proliferation. Results: OTUD3 serves as a deubiquitinase for KPTN. OTUD3 interacts with KPTN, facilitated by the OTU domain within OTUD3. Further investigations confirmed KPTN's ubiquitination modification, primarily at lysine residue 49. Ubiquitination experiments demonstrated OTUD3's ability to mediate KPTN's deubiquitination without affecting its protein levels. This suggests KPTN's ubiquitination is a function-regulated, non-degradable modification. Under various amino acid starvation or stimulation conditions, overexpressing OTUD3 reduces mTORC1 signaling activation, while knocking out OTUD3 further enhances it. Notably, OTUD3's regulation of mTORC1 signaling relies on its deubiquitinase activity, and this effect is observed even in PTEN KO cells, confirming its independence from PTEN, a reported substrate. OTUD3 also promotes GATOR1's lysosomal localization, a process requiring KPTN's involvement. Ultimately, OTUD3 affects cellular metabolic pool products by downregulating the mTORC1 pathway, significantly inhibiting tumor cell growth and proliferation. Discussion: Our experiments shed light on an alternative perspective regarding the intrinsic functions of OTUD3 in inhibiting tumor development. We propose a novel mechanism involving KPTN-mediated regulation of the mTORC1 signaling pathway, offering fresh insights into the occurrence and progression of tumor diseases driven by related genes. This may inspire new approaches for drug screening and cancer treatment, potentially guiding future therapies for relevant tumors.
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Affiliation(s)
- Jiatao Li
- Institutes of Biomedical Sciences, Obstetrics & Gynecology Hospital of Fudan University, Institutes of Metabolism and Integrative Biology, State Key Laboratory of Genetic Engineering, MOE Engineering Research Center of Gene Technology, School of Life Sciences, Fudan University, Shanghai, China
| | - Dan Yang
- Department of Orthopedics, Shanghai Children’s Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Yan Lin
- Institutes of Biomedical Sciences, Obstetrics & Gynecology Hospital of Fudan University, Institutes of Metabolism and Integrative Biology, State Key Laboratory of Genetic Engineering, MOE Engineering Research Center of Gene Technology, School of Life Sciences, Fudan University, Shanghai, China
| | - Wei Xu
- Institutes of Biomedical Sciences, Obstetrics & Gynecology Hospital of Fudan University, Institutes of Metabolism and Integrative Biology, State Key Laboratory of Genetic Engineering, MOE Engineering Research Center of Gene Technology, School of Life Sciences, Fudan University, Shanghai, China
| | - Shi-min Zhao
- Institutes of Biomedical Sciences, Obstetrics & Gynecology Hospital of Fudan University, Institutes of Metabolism and Integrative Biology, State Key Laboratory of Genetic Engineering, MOE Engineering Research Center of Gene Technology, School of Life Sciences, Fudan University, Shanghai, China
| | - Chenji Wang
- Institutes of Biomedical Sciences, Obstetrics & Gynecology Hospital of Fudan University, Institutes of Metabolism and Integrative Biology, State Key Laboratory of Genetic Engineering, MOE Engineering Research Center of Gene Technology, School of Life Sciences, Fudan University, Shanghai, China
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30
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Pérez-Martínez L, Romero L, Verdugo-Sivianes EM, Muñoz-Galván S, Rubio-Mediavilla S, Amiama-Roig A, Carnero A, Blanco JR. Role of maraviroc and/or rapamycin in the liver of IL10 KO mice with frailty syndrome. PLoS One 2024; 19:e0286201. [PMID: 38198476 PMCID: PMC10781157 DOI: 10.1371/journal.pone.0286201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 05/10/2023] [Indexed: 01/12/2024] Open
Abstract
Cellular senescence and low-grade inflammation favor the acceleration of aging. The liver is an essential metabolic organ because changes related to its function are related to age-related diseases. The objective of this study was to evaluate the effects of maraviroc (MVC) and/or rapamycin (RAPA) on liver tissue in an experimental model of frailty syndrome in mice, since MVC and RAPA are two molecules able to decrease CCR5 expression, which is overexpressed in patients with frailty. Methods: Eighty male homozygous IL10KO mice were randomly assigned to one of 4 groups (n = 20): i) IL10KO group; ii) MVC group, iii) RAPA group, and iv) MVC-RAPA group. Liver samples were analyzed. Gene expression quantification and western blotting were also performed. The proinflammatory cytokines IL-6 and IL-18 were decreased in MVC and MVC/RAPA groups, IL-12 was decreased in RAPA and MVC/RAPA groups and TNF-α was decreased in all therapeutic groups. P21 was decreased in RAPA and MVC/RAPA groups, Galactosidase beta-1, was also significantly reduced in all therapeutic groups, as were NF-kB1, NF-kB2 and STAT3. In all groups, mTOR and CCL5 were significantly reduced. CCR5 expression was decreased in the MVC and MVC/RAPA groups. Conclusion: MVC and RAPA may protect against some factors involved in liver aging. More studies will be necessary to verify their clinical applications.
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Affiliation(s)
| | - Lourdes Romero
- Centro de Investigación Biomédica de La Rioja (CIBIR), Logroño, Spain
| | - Eva M. Verdugo-Sivianes
- Instituto de Biomedicina de Sevilla, IBIS, Hospital Universitario Virgen del Rocío, Consejo Superior de Investigaciones Científicas, Universidad de Sevilla, Sevilla, Spain
- CIBERONC, Instituto de Salud Carlos III, Madrid, Spain
| | - Sandra Muñoz-Galván
- Instituto de Biomedicina de Sevilla, IBIS, Hospital Universitario Virgen del Rocío, Consejo Superior de Investigaciones Científicas, Universidad de Sevilla, Sevilla, Spain
- CIBERONC, Instituto de Salud Carlos III, Madrid, Spain
| | | | - Ana Amiama-Roig
- Centro de Investigación Biomédica de La Rioja (CIBIR), Logroño, Spain
| | - Amancio Carnero
- Instituto de Biomedicina de Sevilla, IBIS, Hospital Universitario Virgen del Rocío, Consejo Superior de Investigaciones Científicas, Universidad de Sevilla, Sevilla, Spain
- CIBERONC, Instituto de Salud Carlos III, Madrid, Spain
| | - José-Ramón Blanco
- Centro de Investigación Biomédica de La Rioja (CIBIR), Logroño, Spain
- Servicio de Enfermedades Infecciosas, Hospital Universitario San Pedro, Logroño, Spain
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31
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Alesi N, Khabibullin D, Rosenthal DM, Akl EW, Cory PM, Alchoueiry M, Salem S, Daou M, Gibbons WF, Chen JA, Zhang L, Filippakis H, Graciotti L, Miceli C, Monfregola J, Vilardo C, Morroni M, Di Malta C, Napolitano G, Ballabio A, Henske EP. TFEB drives mTORC1 hyperactivation and kidney disease in Tuberous Sclerosis Complex. Nat Commun 2024; 15:406. [PMID: 38195686 PMCID: PMC10776564 DOI: 10.1038/s41467-023-44229-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 12/05/2023] [Indexed: 01/11/2024] Open
Abstract
Tuberous Sclerosis Complex (TSC) is caused by TSC1 or TSC2 mutations, leading to hyperactivation of mechanistic target of rapamycin complex 1 (mTORC1) and lesions in multiple organs including lung (lymphangioleiomyomatosis) and kidney (angiomyolipoma and renal cell carcinoma). Previously, we found that TFEB is constitutively active in TSC. Here, we generated two mouse models of TSC in which kidney pathology is the primary phenotype. Knockout of TFEB rescues kidney pathology and overall survival, indicating that TFEB is the primary driver of renal disease in TSC. Importantly, increased mTORC1 activity in the TSC2 knockout kidneys is normalized by TFEB knockout. In TSC2-deficient cells, Rheb knockdown or Rapamycin treatment paradoxically increases TFEB phosphorylation at the mTORC1-sites and relocalizes TFEB from nucleus to cytoplasm. In mice, Rapamycin treatment normalizes lysosomal gene expression, similar to TFEB knockout, suggesting that Rapamycin's benefit in TSC is TFEB-dependent. These results change the view of the mechanisms of mTORC1 hyperactivation in TSC and may lead to therapeutic avenues.
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Affiliation(s)
- Nicola Alesi
- Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
| | - Damir Khabibullin
- Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Dean M Rosenthal
- Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Elie W Akl
- Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Pieter M Cory
- Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Michel Alchoueiry
- Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Samer Salem
- Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Melissa Daou
- Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - William F Gibbons
- Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Jennifer A Chen
- Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Long Zhang
- Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Harilaos Filippakis
- Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Laura Graciotti
- Section of Experimental and Technical Sciences, Department of Biomedical Sciences and Public Health, School of Medicine, Università Politecnica delle Marche, Ancona, Italy
| | | | | | | | - Manrico Morroni
- Section of Neuroscience and Cell Biology, Department of Experimental and Clinical Medicine, School of Medicine, Università Politecnica delle Marche, Ancona, Italy
| | - Chiara Di Malta
- Telethon Institute of Genetics and Medicine, Naples, Italy
- Medical Genetics Unit, Department of Medical and Translational Science, Federico II University, Naples, Italy
| | - Gennaro Napolitano
- Telethon Institute of Genetics and Medicine, Naples, Italy
- Medical Genetics Unit, Department of Medical and Translational Science, Federico II University, Naples, Italy
- SSM School for Advanced Studies, Federico II University, Naples, Italy
| | - Andrea Ballabio
- Telethon Institute of Genetics and Medicine, Naples, Italy.
- Medical Genetics Unit, Department of Medical and Translational Science, Federico II University, Naples, Italy.
- SSM School for Advanced Studies, Federico II University, Naples, Italy.
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA.
| | - Elizabeth P Henske
- Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
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32
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Mangione MC, Wen J, Cao DJ. Mechanistic target of rapamycin in regulating macrophage function in inflammatory cardiovascular diseases. J Mol Cell Cardiol 2024; 186:111-124. [PMID: 38039845 PMCID: PMC10843805 DOI: 10.1016/j.yjmcc.2023.10.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 10/14/2023] [Accepted: 10/18/2023] [Indexed: 12/03/2023]
Abstract
The mechanistic target of rapamycin (mTOR) is evolutionarily conserved from yeast to humans and is one of the most fundamental pathways of living organisms. Since its discovery three decades ago, mTOR has been recognized as the center of nutrient sensing and growth, homeostasis, metabolism, life span, and aging. The role of dysregulated mTOR in common diseases, especially cancer, has been extensively studied and reported. Emerging evidence supports that mTOR critically regulates innate immune responses that govern the pathogenesis of various cardiovascular diseases. This review discusses the regulatory role of mTOR in macrophage functions in acute inflammation triggered by ischemia and in atherosclerotic cardiovascular disease (ASCVD) and heart failure with preserved ejection fraction (HFpEF), in which chronic inflammation plays critical roles. Specifically, we discuss the role of mTOR in trained immunity, immune senescence, and clonal hematopoiesis. In addition, this review includes a discussion on the architecture of mTOR, the function of its regulatory complexes, and the dual-arm signals required for mTOR activation to reflect the current knowledge state. We emphasize future research directions necessary to understand better the powerful pathway to take advantage of the mTOR inhibitors for innovative applications in patients with cardiovascular diseases associated with aging and inflammation.
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Affiliation(s)
- MariaSanta C Mangione
- Department of Internal Medicine, Cardiology Division, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jinhua Wen
- Department of Internal Medicine, Cardiology Division, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Dian J Cao
- Department of Internal Medicine, Cardiology Division, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; VA North Texas Health Care System, Dallas TX 75216, USA.
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33
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Tai YT, Fukuda T, Morozumi Y, Hirai H, Oda AH, Kamada Y, Akikusa Y, Kanki T, Ohta K, Shiozaki K. Fission Yeast TORC1 Promotes Cell Proliferation through Sfp1, a Transcription Factor Involved in Ribosome Biogenesis. Mol Cell Biol 2023; 43:675-692. [PMID: 38051102 PMCID: PMC10761059 DOI: 10.1080/10985549.2023.2282349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 11/06/2023] [Indexed: 12/07/2023] Open
Abstract
Target of rapamycin complex 1 (TORC1) is activated in response to nutrient availability and growth factors, promoting cellular anabolism and proliferation. To explore the mechanism of TORC1-mediated proliferation control, we performed a genetic screen in fission yeast and identified Sfp1, a zinc-finger transcription factor, as a multicopy suppressor of temperature-sensitive TORC1 mutants. Our observations suggest that TORC1 phosphorylates Sfp1 and protects Sfp1 from proteasomal degradation. Transcription analysis revealed that Sfp1 positively regulates genes involved in ribosome production together with two additional transcription factors, Ifh1/Crf1 and Fhl1. Ifh1 physically interacts with Fhl1, and the nuclear localization of Ifh1 is regulated in response to nutrient levels in a manner dependent on TORC1 and Sfp1. Taken together, our data suggest that the transcriptional regulation of the genes involved in ribosome biosynthesis by Sfp1, Ifh1, and Fhl1 is one of the key pathways through which nutrient-activated TORC1 promotes cell proliferation.
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Affiliation(s)
- Yen Teng Tai
- Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Nara, Japan
| | - Tomoyuki Fukuda
- Department of Cellular Physiology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Yuichi Morozumi
- Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Nara, Japan
| | - Hayato Hirai
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
| | - Arisa H. Oda
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
| | - Yoshiaki Kamada
- National Institute for Basic Biology, Okazaki, Aichi, Japan
- Graduate University for Advanced Studies (SOKENDAI), Hayama, Kanagawa, Japan
| | - Yutaka Akikusa
- Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Nara, Japan
| | - Tomotake Kanki
- Department of Cellular Physiology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Kunihiro Ohta
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
| | - Kazuhiro Shiozaki
- Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Nara, Japan
- Department of Microbiology and Molecular Genetics, University of California, Davis, California, USA
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Xie Y, Zhao G, Lei X, Cui N, Wang H. Advances in the regulatory mechanisms of mTOR in necroptosis. Front Immunol 2023; 14:1297408. [PMID: 38164133 PMCID: PMC10757967 DOI: 10.3389/fimmu.2023.1297408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 12/01/2023] [Indexed: 01/03/2024] Open
Abstract
The mammalian target of rapamycin (mTOR), an evolutionarily highly conserved serine/threonine protein kinase, plays a prominent role in controlling gene expression, metabolism, and cell death. Programmed cell death (PCD) is indispensable for maintaining homeostasis by removing senescent, defective, or malignant cells. Necroptosis, a type of PCD, relies on the interplay between receptor-interacting serine-threonine kinases (RIPKs) and the membrane perforation by mixed lineage kinase domain-like protein (MLKL), which is distinguished from apoptosis. With the development of necroptosis-regulating mechanisms, the importance of mTOR in the complex network of intersecting signaling pathways that govern the process has become more evident. mTOR is directly responsible for the regulation of RIPKs. Autophagy is an indirect mechanism by which mTOR regulates the removal and interaction of RIPKs. Another necroptosis trigger is reactive oxygen species (ROS) produced by oxidative stress; mTOR regulates necroptosis by exploiting ROS. Considering the intricacy of the signal network, it is reasonable to assume that mTOR exerts a bifacial effect on necroptosis. However, additional research is necessary to elucidate the underlying mechanisms. In this review, we summarized the mechanisms underlying mTOR activation and necroptosis and highlighted the signaling pathway through which mTOR regulates necroptosis. The development of therapeutic targets for various diseases has been greatly advanced by the expanding knowledge of how mTOR regulates necroptosis.
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Affiliation(s)
- Yawen Xie
- Department of Critical Care Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Guoyu Zhao
- Department of Critical Care Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Xianli Lei
- Department of Critical Care Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Na Cui
- Department of Critical Care Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Hao Wang
- Department of Critical Care Medicine, Beijing Jishuitan Hospital, Capital Medical University, Beijing, China
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Cecil JH, Padilla CM, Lipinski AA, Langlais PR, Luo X, Capaldi AP. The Molecular Logic of Gtr1/2 and Pib2 Dependent TORC1 Regulation in Budding Yeast. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.06.570342. [PMID: 38106135 PMCID: PMC10723367 DOI: 10.1101/2023.12.06.570342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
The Target of Rapamycin kinase Complex I (TORC1) regulates cell growth and metabolism in eukaryotes. Previous studies have shown that, in Saccharomyces cerevisiae, nitrogen and amino acid signals activate TORC1 via the highly conserved small GTPases, Gtr1/2, and the phosphatidylinositol 3-phosphate binding protein, Pib2. However, it was unclear if/how Gtr1/2 and Pib2 cooperate to control TORC1. Here we report that this dual regulator system pushes TORC1 into three distinct signaling states: (i) a Gtr1/2 on, Pib2 on, rapid growth state in nutrient replete conditions; (ii) a Gtr1/2 off, Pib2 on, adaptive/slow growth state in poor-quality growth medium; and (iii) a Gtr1/2 off, Pib2 off, quiescent state in starvation conditions. We suggest that other signaling pathways work in a similar way, to drive a multi-level response via a single kinase, but the behavior has been overlooked since most studies follow signaling to a single reporter protein.
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Affiliation(s)
- Jacob H. Cecil
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ, 85721
| | - Cristina M. Padilla
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ, 85721
| | | | - Paul R. Langlais
- Department of Medicine, University of Arizona, Tucson, AZ, 85721
| | - Xiangxia Luo
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ, 85721
| | - Andrew P. Capaldi
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ, 85721
- Bio5 Institute, University of Arizona, Tucson, AZ, 85721
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36
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Ge MK, Zhang C, Zhang N, He P, Cai HY, Li S, Wu S, Chu XL, Zhang YX, Ma HM, Xia L, Yang S, Yu JX, Yao SY, Zhou XL, Su B, Chen GQ, Shen SM. The tRNA-GCN2-FBXO22-axis-mediated mTOR ubiquitination senses amino acid insufficiency. Cell Metab 2023; 35:2216-2230.e8. [PMID: 37979583 DOI: 10.1016/j.cmet.2023.10.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 07/26/2023] [Accepted: 10/26/2023] [Indexed: 11/20/2023]
Abstract
Mammalian target of rapamycin complex 1 (mTORC1) monitors cellular amino acid changes for function, but the molecular mediators of this process remain to be fully defined. Here, we report that depletion of cellular amino acids, either alone or in combination, leads to the ubiquitination of mTOR, which inhibits mTORC1 kinase activity by preventing substrate recruitment. Mechanistically, amino acid depletion causes accumulation of uncharged tRNAs, thereby stimulating GCN2 to phosphorylate FBXO22, which in turn accrues in the cytoplasm and ubiquitinates mTOR at Lys2066 in a K27-linked manner. Accordingly, mutation of mTOR Lys2066 abolished mTOR ubiquitination in response to amino acid depletion, rendering mTOR insensitive to amino acid starvation both in vitro and in vivo. Collectively, these data reveal a novel mechanism of amino acid sensing by mTORC1 via a previously unknown GCN2-FBXO22-mTOR pathway that is uniquely controlled by uncharged tRNAs.
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Affiliation(s)
- Meng-Kai Ge
- Institute of Aging & Tissue Regeneration, State Key Laboratory of Systems Medicine for Cancer and Stress and Cancer Research Unit of Chinese Academy of Medical Sciences (No. 2019RU043), Ren-Ji Hospital, Shanghai Jiao Tong University School of Medicine (SJTU-SM), Shanghai 200127, China; Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, SJTU-SM, Shanghai 200025, China
| | - Cheng Zhang
- Institute of Aging & Tissue Regeneration, State Key Laboratory of Systems Medicine for Cancer and Stress and Cancer Research Unit of Chinese Academy of Medical Sciences (No. 2019RU043), Ren-Ji Hospital, Shanghai Jiao Tong University School of Medicine (SJTU-SM), Shanghai 200127, China
| | - Na Zhang
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, SJTU-SM, Shanghai 200025, China
| | - Ping He
- Institute of Aging & Tissue Regeneration, State Key Laboratory of Systems Medicine for Cancer and Stress and Cancer Research Unit of Chinese Academy of Medical Sciences (No. 2019RU043), Ren-Ji Hospital, Shanghai Jiao Tong University School of Medicine (SJTU-SM), Shanghai 200127, China
| | - Hai-Yan Cai
- Department of Hematology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Song Li
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, SJTU-SM, Shanghai 200025, China
| | - Shuai Wu
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, SJTU-SM, Shanghai 200025, China
| | - Xi-Li Chu
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, SJTU-SM, Shanghai 200025, China
| | - Yu-Xue Zhang
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, SJTU-SM, Shanghai 200025, China
| | - Hong-Ming Ma
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, SJTU-SM, Shanghai 200025, China
| | - Li Xia
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, SJTU-SM, Shanghai 200025, China
| | - Shuo Yang
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, SJTU-SM, Shanghai 200025, China
| | - Jian-Xiu Yu
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, SJTU-SM, Shanghai 200025, China
| | - Shi-Ying Yao
- State Key Laboratory of Molecular Biology, Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Xiao-Long Zhou
- State Key Laboratory of Molecular Biology, Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Bing Su
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, SJTU-SM, Shanghai 200025, China.
| | - Guo-Qiang Chen
- Institute of Aging & Tissue Regeneration, State Key Laboratory of Systems Medicine for Cancer and Stress and Cancer Research Unit of Chinese Academy of Medical Sciences (No. 2019RU043), Ren-Ji Hospital, Shanghai Jiao Tong University School of Medicine (SJTU-SM), Shanghai 200127, China; Hainan Academy of Medical Sciences, Hainan Medical University, Hainan 571199, China.
| | - Shao-Ming Shen
- Institute of Aging & Tissue Regeneration, State Key Laboratory of Systems Medicine for Cancer and Stress and Cancer Research Unit of Chinese Academy of Medical Sciences (No. 2019RU043), Ren-Ji Hospital, Shanghai Jiao Tong University School of Medicine (SJTU-SM), Shanghai 200127, China; Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, SJTU-SM, Shanghai 200025, China.
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Goul C, Peruzzo R, Zoncu R. The molecular basis of nutrient sensing and signalling by mTORC1 in metabolism regulation and disease. Nat Rev Mol Cell Biol 2023; 24:857-875. [PMID: 37612414 DOI: 10.1038/s41580-023-00641-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/06/2023] [Indexed: 08/25/2023]
Abstract
The Ser/Thr kinase mechanistic target of rapamycin (mTOR) is a central regulator of cellular metabolism. As part of mTOR complex 1 (mTORC1), mTOR integrates signals such as the levels of nutrients, growth factors, energy sources and oxygen, and triggers responses that either boost anabolism or suppress catabolism. mTORC1 signalling has wide-ranging consequences for the growth and homeostasis of key tissues and organs, and its dysregulated activity promotes cancer, type 2 diabetes, neurodegeneration and other age-related disorders. How mTORC1 integrates numerous upstream cues and translates them into specific downstream responses is an outstanding question with major implications for our understanding of physiology and disease mechanisms. In this Review, we discuss recent structural and functional insights into the molecular architecture of mTORC1 and its lysosomal partners, which have greatly increased our mechanistic understanding of nutrient-dependent mTORC1 regulation. We also discuss the emerging involvement of aberrant nutrient-mTORC1 signalling in multiple diseases.
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Affiliation(s)
- Claire Goul
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Roberta Peruzzo
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Roberto Zoncu
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.
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38
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Khalil MI, Ali MM, Holail J, Houssein M. Growth or death? Control of cell destiny by mTOR and autophagy pathways. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2023; 185:39-55. [PMID: 37944568 DOI: 10.1016/j.pbiomolbio.2023.10.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 10/08/2023] [Accepted: 10/23/2023] [Indexed: 11/12/2023]
Abstract
One of the central regulators of cell growth, proliferation, and metabolism is the mammalian target of rapamycin, mTOR, which exists in two structurally and functionally different complexes: mTORC1 and mTORC2; unlike m TORC2, mTORC1 is activated in response to the sufficiency of nutrients and is inhibited by rapamycin. mTOR complexes have critical roles not only in protein synthesis, gene transcription regulation, proliferation, tumor metabolism, but also in the regulation of the programmed cell death mechanisms such as autophagy and apoptosis. Autophagy is a conserved catabolic mechanism in which damaged molecules are recycled in response to nutrient starvation. Emerging evidence indicates that the mTOR signaling pathway is frequently activated in tumors. In addition, dysregulation of autophagy was associated with the development of a variety of human diseases, such as cancer and aging. Since mTOR can inhibit the induction of the autophagic process from the early stages of autophagosome formation to the late stage of lysosome degradation, the use of mTOR inhibitors to regulate autophagy could be considered a potential therapeutic option. The present review sheds light on the mTOR and autophagy signaling pathways and the mechanisms of regulation of mTOR-autophagy.
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Affiliation(s)
- Mahmoud I Khalil
- Department of Biological Sciences, Faculty of Science, Beirut Arab University, Beirut, 11072809, Lebanon; Molecular Biology Unit, Department of Zoology, Faculty of Science, Alexandria University, Alexandria, 21511, Egypt.
| | - Mohamad M Ali
- Department of Medical Biochemistry and Microbiology, Science for Life Laboratory, Uppsala University, SE-751 23, Uppsala, Sweden.
| | - Jasmine Holail
- Department of Biochemistry and Molecular Medicine, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia; Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom.
| | - Marwa Houssein
- Department of Biological Sciences, Faculty of Science, Beirut Arab University, Beirut, 11072809, Lebanon.
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39
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Takla M, Keshri S, Rubinsztein DC. The post-translational regulation of transcription factor EB (TFEB) in health and disease. EMBO Rep 2023; 24:e57574. [PMID: 37728021 PMCID: PMC10626434 DOI: 10.15252/embr.202357574] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 08/10/2023] [Accepted: 08/25/2023] [Indexed: 09/21/2023] Open
Abstract
Transcription factor EB (TFEB) is a basic helix-loop-helix leucine zipper transcription factor that acts as a master regulator of lysosomal biogenesis, lysosomal exocytosis, and macro-autophagy. TFEB contributes to a wide range of physiological functions, including mitochondrial biogenesis and innate and adaptive immunity. As such, TFEB is an essential component of cellular adaptation to stressors, ranging from nutrient deprivation to pathogenic invasion. The activity of TFEB depends on its subcellular localisation, turnover, and DNA-binding capacity, all of which are regulated at the post-translational level. Pathological states are characterised by a specific set of stressors, which elicit post-translational modifications that promote gain or loss of TFEB function in the affected tissue. In turn, the resulting increase or decrease in survival of the tissue in which TFEB is more or less active, respectively, may either benefit or harm the organism as a whole. In this way, the post-translational modifications of TFEB account for its otherwise paradoxical protective and deleterious effects on organismal fitness in diseases ranging from neurodegeneration to cancer. In this review, we describe how the intracellular environment characteristic of different diseases alters the post-translational modification profile of TFEB, enabling cellular adaptation to a particular pathological state.
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Affiliation(s)
- Michael Takla
- Department of Medical Genetics, Cambridge Institute for Medical Research (CIMR)University of CambridgeCambridgeUK
- UK Dementia Research Institute, Cambridge Institute for Medical Research (CIMR)University of CambridgeCambridgeUK
| | - Swati Keshri
- Department of Medical Genetics, Cambridge Institute for Medical Research (CIMR)University of CambridgeCambridgeUK
- UK Dementia Research Institute, Cambridge Institute for Medical Research (CIMR)University of CambridgeCambridgeUK
| | - David C Rubinsztein
- Department of Medical Genetics, Cambridge Institute for Medical Research (CIMR)University of CambridgeCambridgeUK
- UK Dementia Research Institute, Cambridge Institute for Medical Research (CIMR)University of CambridgeCambridgeUK
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40
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Wehle DT, Bass CS, Sulc J, Mirzaa G, Smith SEP. Protein interaction network analysis of mTOR signaling reveals modular organization. J Biol Chem 2023; 299:105271. [PMID: 37741456 PMCID: PMC10594569 DOI: 10.1016/j.jbc.2023.105271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 09/11/2023] [Accepted: 09/13/2023] [Indexed: 09/25/2023] Open
Abstract
The mammalian target of rapamycin (mTOR) is a serine-threonine kinase that acts as a central mediator of translation and plays important roles in cell growth, synaptic plasticity, cancer, and a wide range of developmental disorders. The signaling cascade linking lipid kinases (phosphoinositide 3-kinases), protein kinases (AKT), and translation initiation complexes (EIFs) to mTOR has been extensively modeled, but does not fully describe mTOR system behavior. Here, we use quantitative multiplex coimmunoprecipitation to monitor a protein interaction network (PIN) composed of 300+ binary interactions among mTOR-related proteins. Using a simple model system of serum-deprived or fresh-media-fed mouse 3T3 fibroblasts, we observed extensive PIN remodeling involving 27+ individual protein interactions after 1 h, despite phosphorylation changes observed after only 5 min. Using small molecule inhibitors of phosphoinositide 3-kinase, AKT, mTOR, MEK and ERK, we define subsets of the PIN, termed "modules", that respond differently to each inhibitor. Using primary fibroblasts from individuals with overgrowth disorders caused by pathogenic PIK3CA or MTOR variants, we find that hyperactivation of mTOR pathway components is reflected in a hyperactive PIN. Our data define a "modular" organization of the mTOR PIN in which coordinated groups of interactions respond to the activation or inhibition of distinct nodes, and demonstrate that kinase inhibitors affect the modular network architecture in a complex manner, inconsistent with simple linear models of signal transduction.
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Affiliation(s)
- Devin T Wehle
- Graduate Program in Neuroscience, University of Washington, Seattle, Washington, USA; Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington, USA
| | - Carter S Bass
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington, USA
| | - Josef Sulc
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington, USA
| | - Ghayda Mirzaa
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington, USA; Department of Pediatrics, University of Washington School of Medicine, Seattle, Washington, USA; Brotman Baty Institute for Precision Medicine, Seattle, Washington, USA
| | - Stephen E P Smith
- Graduate Program in Neuroscience, University of Washington, Seattle, Washington, USA; Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington, USA; Department of Pediatrics, University of Washington School of Medicine, Seattle, Washington, USA.
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41
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Sri Hari A, Banerji R, Liang LP, Fulton RE, Huynh CQ, Fabisiak T, McElroy PB, Roede JR, Patel M. Increasing glutathione levels by a novel posttranslational mechanism inhibits neuronal hyperexcitability. Redox Biol 2023; 67:102895. [PMID: 37769522 PMCID: PMC10539966 DOI: 10.1016/j.redox.2023.102895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 09/14/2023] [Accepted: 09/18/2023] [Indexed: 10/02/2023] Open
Abstract
Glutathione (GSH) depletion, and impaired redox homeostasis have been observed in experimental animal models and patients with epilepsy. Pleiotropic strategies that elevate GSH levels via transcriptional regulation have been shown to significantly decrease oxidative stress and seizure frequency, increase seizure threshold, and rescue certain cognitive deficits. Whether elevation of GSH per se alters neuronal hyperexcitability remains unanswered. We previously showed that thiols such as dimercaprol (DMP) elevate GSH via post-translational activation of glutamate cysteine ligase (GCL), the rate limiting GSH biosynthetic enzyme. Here, we asked if elevation of cellular GSH by DMP altered neuronal hyperexcitability in-vitro and in-vivo. Treatment of primary neuronal-glial cerebrocortical cultures with DMP elevated GSH and inhibited a voltage-gated potassium channel blocker (4-aminopyridine, 4AP) induced neuronal hyperexcitability. DMP increased GSH in wildtype (WT) zebrafish larvae and significantly attenuated convulsant pentylenetetrazol (PTZ)-induced acute 'seizure-like' swim behavior. DMP treatment increased GSH and inhibited convulsive, spontaneous 'seizure-like' swim behavior in the Dravet Syndrome (DS) zebrafish larvae (scn1Lab). Furthermore, DMP treatment significantly decreased spontaneous electrographic seizures and associated seizure parameters in scn1Lab zebrafish larvae. We investigated the role of the redox-sensitive mammalian target of rapamycin (mTOR) pathway due to the presence of several cysteine-rich proteins and their involvement in regulating neuronal excitability. Treatment of primary neuronal-glial cerebrocortical cultures with 4AP or l-buthionine-(S,R)-sulfoximine (BSO), an irreversible inhibitor of GSH biosynthesis, significantly increased mTOR complex I (mTORC1) activity which was rescued by pre-treatment with DMP. Furthermore, BSO-mediated GSH depletion oxidatively modified the tuberous sclerosis protein complex (TSC) consisting of hamartin (TSC1), tuberin (TSC2), and TBC1 domain family member 7 (TBC1D7) which are critical negative regulators of mTORC1. In summary, our results suggest that DMP-mediated GSH elevation by a novel post-translational mechanism can inhibit neuronal hyperexcitability both in-vitro and in-vivo and a plausible link is the redox sensitive mTORC1 pathway.
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Affiliation(s)
- Ashwini Sri Hari
- Department of Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Rajeswari Banerji
- Department of Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Li-Ping Liang
- Department of Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Ruth E Fulton
- Department of Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Christopher Quoc Huynh
- Department of Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Timothy Fabisiak
- Department of Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Pallavi Bhuyan McElroy
- The Janssen Pharmaceutical Companies of Johnson & Johnson, Greater Philadelphia Area, Horsham, PA, 19044, USA
| | - James R Roede
- Department of Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Manisha Patel
- Department of Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, Aurora, CO, 80045, USA.
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Tae K, Kim SJ, Cho SW, Lee H, Cha HS, Choi CY. L-Type Amino Acid Transporter 1 (LAT1) Promotes PMA-Induced Cell Migration through mTORC2 Activation at the Lysosome. Cells 2023; 12:2504. [PMID: 37887348 PMCID: PMC10605051 DOI: 10.3390/cells12202504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 10/17/2023] [Accepted: 10/20/2023] [Indexed: 10/28/2023] Open
Abstract
The mTOR signaling pathway integrates signaling inputs from nutrients, including glucose and amino acids, which are precisely regulated by transporters depending on nutrient levels. The L-type amino acid transporter 1 (LAT1) affects the activity of mTORC1 through upstream regulators that sense intracellular amino acid levels. While mTORC1 activation by LAT1 has been thoroughly investigated in cultured cells, the effects of LAT1 expression on the activity of mTORC2 has scarcely been studied. Here, we provide evidence that LAT1 recruits and activates mTORC2 on the lysosome for PMA-induced cell migration. LAT1 is translocated to the lysosomes in cells treated with PMA in a dose- and time-dependent manner. Lysosomal LAT1 interacted with mTORC2 through a direct interaction with Rictor, leading to the lysosomal localization of mTORC2. Furthermore, the depletion of LAT1 reduced PMA-induced cell migration in a wound-healing assay. Consistent with these results, the LAT1 N3KR mutant, which is defective in PMA-induced endocytosis and lysosomal localization, did not induce mTORC2 recruitment to the lysosome, with the activation of mTORC2 determined via Akt phosphorylation or the LAT1-mediated promotion of cell migration. Taken together, lysosomal LAT1 recruits and activates the mTORC2 complex and downstream Akt for PMA-mediated cell migration. These results provide insights into the development of therapeutic drugs targeting the LAT1 amino acid transporter to block metastasis, as well as disease progression in various types of cancer.
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Affiliation(s)
| | | | | | | | | | - Cheol-Yong Choi
- Department of Biological Sciences, Sungkyunkwan University, Suwon 16419, Republic of Korea; (K.T.); (S.-J.K.); (S.-W.C.); (H.L.); (H.-S.C.)
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43
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Vujovic F, Shepherd CE, Witting PK, Hunter N, Farahani RM. Redox-Mediated Rewiring of Signalling Pathways: The Role of a Cellular Clock in Brain Health and Disease. Antioxidants (Basel) 2023; 12:1873. [PMID: 37891951 PMCID: PMC10604469 DOI: 10.3390/antiox12101873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 10/14/2023] [Accepted: 10/15/2023] [Indexed: 10/29/2023] Open
Abstract
Metazoan signalling pathways can be rewired to dampen or amplify the rate of events, such as those that occur in development and aging. Given that a linear network topology restricts the capacity to rewire signalling pathways, such scalability of the pace of biological events suggests the existence of programmable non-linear elements in the underlying signalling pathways. Here, we review the network topology of key signalling pathways with a focus on redox-sensitive proteins, including PTEN and Ras GTPase, that reshape the connectivity profile of signalling pathways in response to an altered redox state. While this network-level impact of redox is achieved by the modulation of individual redox-sensitive proteins, it is the population by these proteins of critical nodes in a network topology of signal transduction pathways that amplifies the impact of redox-mediated reprogramming. We propose that redox-mediated rewiring is essential to regulate the rate of transmission of biological signals, giving rise to a programmable cellular clock that orchestrates the pace of biological phenomena such as development and aging. We further review the evidence that an aberrant redox-mediated modulation of output of the cellular clock contributes to the emergence of pathological conditions affecting the human brain.
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Affiliation(s)
- Filip Vujovic
- IDR/Westmead Institute for Medical Research, Sydney, NSW 2145, Australia; (F.V.); (N.H.)
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2006, Australia
| | | | - Paul K. Witting
- Redox Biology Group, Charles Perkins Centre, Faculty of Medicine and Health, School of Medical Sciences, The University of Sydney, Sydney, NSW 2006, Australia;
| | - Neil Hunter
- IDR/Westmead Institute for Medical Research, Sydney, NSW 2145, Australia; (F.V.); (N.H.)
| | - Ramin M. Farahani
- IDR/Westmead Institute for Medical Research, Sydney, NSW 2145, Australia; (F.V.); (N.H.)
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2006, Australia
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44
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Xu J, Bradley N, He Y. Structure and function of the apical PIKKs in double-strand break repair. Curr Opin Struct Biol 2023; 82:102651. [PMID: 37437397 PMCID: PMC10530350 DOI: 10.1016/j.sbi.2023.102651] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 06/15/2023] [Accepted: 06/16/2023] [Indexed: 07/14/2023]
Abstract
Members of the phosphatidylinositol 3' kinase (PI3K)-related kinases (PIKKs) family, including DNA-dependent protein kinase catalytic subunit (DNA-PKcs), ataxia telangiectasia mutated (ATM), ataxia-telangiectasia mutated and Rad3-related (ATR), mammalian target of rapamycin (mTOR), suppressor with morphological effect on genitalia 1 (SMG1), and transformation/transcription domain-associated protein 1 (TRRAP/Tra1), participate in a variety of physiological processes, such as cell-cycle control, metabolism, transcription, replication, and the DNA damage response. In eukaryotic cells, DNA-PKcs, ATM, and ATR-ATRIP are the main sensors and regulators of DNA double-strand break repair. The purpose of this review is to describe recent structures of DNA-PKcs, ATM, and ATR, as well as their functions in activation and phosphorylation in different DNA repair pathways.
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Affiliation(s)
- Jingfei Xu
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, USA
| | - Noah Bradley
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, USA
| | - Yuan He
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, USA.
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45
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Linde-Garelli KY, Rogala KB. Structural mechanisms of the mTOR pathway. Curr Opin Struct Biol 2023; 82:102663. [PMID: 37572585 DOI: 10.1016/j.sbi.2023.102663] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 07/01/2023] [Accepted: 07/07/2023] [Indexed: 08/14/2023]
Abstract
The mTOR signaling pathway is essential for regulating cell growth and mammalian metabolism. The mTOR kinase forms two complexes, mTORC1 and mTORC2, which respond to external stimuli and regulate differential downstream targets. Cellular membrane-associated translocation mediates function and assembly of the mTOR complexes, and recent structural studies have begun uncovering the molecular basis by which the mTOR pathway (1) regulates signaling inputs, (2) recruits substrates, (3) localizes to biological membranes, and (4) becomes activated. Moreover, indications of dysregulated mTOR signaling are implicated in a wide range of diseases and an increasingly comprehensive understanding of structural mechanisms is driving novel translational development.
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Affiliation(s)
- Karen Y Linde-Garelli
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA; Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, USA; Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA, USA
| | - Kacper B Rogala
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA; Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, USA; Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA, USA.
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46
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Chen C, Zhu T, Gong L, Hu Z, Wei H, Fan J, Lin D, Wang X, Xu J, Dong X, Wang Y, Xia N, Zeng L, Jiang P, Xie Y. Trpm2 deficiency in microglia attenuates neuroinflammation during epileptogenesis by upregulating autophagy via the AMPK/mTOR pathway. Neurobiol Dis 2023; 186:106273. [PMID: 37648036 DOI: 10.1016/j.nbd.2023.106273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 08/15/2023] [Accepted: 08/27/2023] [Indexed: 09/01/2023] Open
Abstract
Epilepsy is one of the most common neurological disorders. Neuroinflammation involving the activation of microglia and astrocytes constitutes an important and common mechanism in epileptogenesis. Transient receptor potential melastatin 2 (TRPM2) is a calcium-permeable, non-selective cation channel that plays pathological roles in various inflammation-related diseases. Our previous study demonstrated that Trpm2 knockout exhibits therapeutic effects on pilocarpine-induced glial activation and neuroinflammation. However, whether TRPM2 in microglia and astrocytes plays a common pathogenic role in this process and the underlying molecular mechanisms remained undetermined. Here, we demonstrate a previously unknown role for microglial TRPM2 in epileptogenesis. Trpm2 knockout in microglia attenuated kainic acid (KA)-induced glial activation, inflammatory cytokines production and hippocampal paroxysmal discharges, whereas Trpm2 knockout in astrocytes exhibited no significant effects. Furthermore, we discovered that these therapeutic effects were mediated by upregulated autophagy via the adenosine monophosphate activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR) pathway in microglia. Thus, our findings highlight an important deleterious role of microglial TRPM2 in temporal lobe epilepsy.
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Affiliation(s)
- Chen Chen
- Department of Neurology, Department of Neurobiology and Department of Rehabilitation, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center For Child Health, Hangzhou 310052, China
| | - Tao Zhu
- Department of Critical Care Medicine, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310030, China
| | - Lifen Gong
- Department of Neurology, Department of Neurobiology and Department of Rehabilitation, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center For Child Health, Hangzhou 310052, China
| | - Zhe Hu
- Department of Neurology, Department of Neurobiology and Department of Rehabilitation, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center For Child Health, Hangzhou 310052, China
| | - Hao Wei
- Department of Pharmacy, Xuzhou Medical University, 221004 Xuzhou, China
| | - Jianchen Fan
- Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Hangzhou City University, Hangzhou 310015, China
| | - Donghui Lin
- Department of Neurology, Department of Neurobiology and Department of Rehabilitation, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center For Child Health, Hangzhou 310052, China
| | - Xiaojun Wang
- Department of Neurology, Department of Neurobiology and Department of Rehabilitation, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center For Child Health, Hangzhou 310052, China
| | - Junyu Xu
- Department of Neurology, Department of Neurobiology and Department of Rehabilitation, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center For Child Health, Hangzhou 310052, China
| | - Xinyan Dong
- Department of Neurology, Department of Neurobiology and Department of Rehabilitation, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center For Child Health, Hangzhou 310052, China
| | - Yifan Wang
- Department of Neurology, Department of Neurobiology and Department of Rehabilitation, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center For Child Health, Hangzhou 310052, China
| | - Ningxiao Xia
- Department of Neurology, Department of Neurobiology and Department of Rehabilitation, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center For Child Health, Hangzhou 310052, China
| | - Linghui Zeng
- Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Hangzhou City University, Hangzhou 310015, China
| | - Peifang Jiang
- Department of Neurology, Department of Neurobiology and Department of Rehabilitation, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center For Child Health, Hangzhou 310052, China.
| | - Yicheng Xie
- Department of Neurology, Department of Neurobiology and Department of Rehabilitation, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center For Child Health, Hangzhou 310052, China.
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47
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Howes AC, Perisic O, Williams RL. Structural insights into the activation of ataxia-telangiectasia mutated by oxidative stress. SCIENCE ADVANCES 2023; 9:eadi8291. [PMID: 37756394 PMCID: PMC10530080 DOI: 10.1126/sciadv.adi8291] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Accepted: 08/24/2023] [Indexed: 09/29/2023]
Abstract
Ataxia-telangiectasia mutated (ATM) is a master kinase regulating DNA damage response that is activated by DNA double-strand breaks. However, ATM is also directly activated by reactive oxygen species, but how oxidative activation is achieved remains unknown. We determined the cryo-EM structure of an H2O2-activated ATM and showed that under oxidizing conditions, ATM formed an intramolecular disulfide bridge between two protomers that are rotated relative to each other when compared to the basal state. This rotation is accompanied by release of the substrate-blocking PRD region and twisting of the N-lobe relative to the C-lobe, which greatly optimizes catalysis. This active site remodeling enabled us to capture a substrate (p53) bound to the enzyme. This provides the first structural insights into how ATM is activated during oxidative stress.
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Affiliation(s)
| | - Olga Perisic
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
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48
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Pokorzynski ND, Groisman EA. How Bacterial Pathogens Coordinate Appetite with Virulence. Microbiol Mol Biol Rev 2023; 87:e0019822. [PMID: 37358444 PMCID: PMC10521370 DOI: 10.1128/mmbr.00198-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/27/2023] Open
Abstract
Cells adjust growth and metabolism to nutrient availability. Having access to a variety of carbon sources during infection of their animal hosts, facultative intracellular pathogens must efficiently prioritize carbon utilization. Here, we discuss how carbon source controls bacterial virulence, with an emphasis on Salmonella enterica serovar Typhimurium, which causes gastroenteritis in immunocompetent humans and a typhoid-like disease in mice, and propose that virulence factors can regulate carbon source prioritization by modifying cellular physiology. On the one hand, bacterial regulators of carbon metabolism control virulence programs, indicating that pathogenic traits appear in response to carbon source availability. On the other hand, signals controlling virulence regulators may impact carbon source utilization, suggesting that stimuli that bacterial pathogens experience within the host can directly impinge on carbon source prioritization. In addition, pathogen-triggered intestinal inflammation can disrupt the gut microbiota and thus the availability of carbon sources. By coordinating virulence factors with carbon utilization determinants, pathogens adopt metabolic pathways that may not be the most energy efficient because such pathways promote resistance to antimicrobial agents and also because host-imposed deprivation of specific nutrients may hinder the operation of certain pathways. We propose that metabolic prioritization by bacteria underlies the pathogenic outcome of an infection.
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Affiliation(s)
- Nick D. Pokorzynski
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
| | - Eduardo A. Groisman
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
- Yale Microbial Sciences Institute, West Haven, Connecticut, USA
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49
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Tettoni SD, Egri SB, Doxsey DD, Veinotte K, Ouch C, Chang JY, Song K, Xu C, Shen K. Structure of the Schizosaccharomyces pombe Gtr-Lam complex reveals evolutionary divergence of mTORC1-dependent amino acid sensing. Structure 2023; 31:1065-1076.e5. [PMID: 37453417 PMCID: PMC10529327 DOI: 10.1016/j.str.2023.06.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 05/14/2023] [Accepted: 06/19/2023] [Indexed: 07/18/2023]
Abstract
mTORC1 is a protein kinase complex that controls cellular growth in response to nutrient availability. Amino acid signals are transmitted toward mTORC1 via the Rag/Gtr GTPases and their upstream regulators. An important regulator is LAMTOR, which localizes Rag/Gtr on the lysosomal/vacuole membrane. In human cells, LAMTOR consists of five subunits, but in yeast, only three or four. Currently, it is not known how variation of the subunit stoichiometry may affect its structural organization and biochemical properties. Here, we report a 3.1 Å-resolution structural model of the Gtr-Lam complex in Schizosaccharomyces pombe. We found that SpGtr shares conserved architecture as HsRag, but the intersubunit communication that coordinates nucleotide loading on the two subunits differs. In contrast, SpLam contains distinctive structural features, but its GTP-specific GEF activity toward SpGtr is evolutionarily conserved. Our results revealed unique evolutionary paths of the protein components of the mTORC1 pathway.
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Affiliation(s)
- Steven D Tettoni
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, 373 Plantation Street, Worcester, MA 01605, USA
| | - Shawn B Egri
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, 373 Plantation Street, Worcester, MA 01605, USA
| | - Dylan D Doxsey
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, 373 Plantation Street, Worcester, MA 01605, USA
| | - Kristen Veinotte
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, 373 Plantation Street, Worcester, MA 01605, USA
| | - Christna Ouch
- Department of Biochemistry & Molecular Biotechnology, University of Massachusetts Chan Medical School, 364 Plantation Street, Worcester, MA 01605, USA
| | - Jeng-Yih Chang
- Department of Biochemistry & Molecular Biotechnology, University of Massachusetts Chan Medical School, 364 Plantation Street, Worcester, MA 01605, USA
| | - Kangkang Song
- Department of Biochemistry & Molecular Biotechnology, University of Massachusetts Chan Medical School, 364 Plantation Street, Worcester, MA 01605, USA
| | - Chen Xu
- Department of Biochemistry & Molecular Biotechnology, University of Massachusetts Chan Medical School, 364 Plantation Street, Worcester, MA 01605, USA
| | - Kuang Shen
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, 373 Plantation Street, Worcester, MA 01605, USA; Department of Biochemistry & Molecular Biotechnology, University of Massachusetts Chan Medical School, 364 Plantation Street, Worcester, MA 01605, USA.
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50
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Kazyken D, Lentz SI, Wadley M, Fingar DC. Alkaline intracellular pH (pHi) increases PI3K activity to promote mTORC1 and mTORC2 signaling and function during growth factor limitation. J Biol Chem 2023; 299:105097. [PMID: 37507012 PMCID: PMC10477693 DOI: 10.1016/j.jbc.2023.105097] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 07/14/2023] [Accepted: 07/17/2023] [Indexed: 07/30/2023] Open
Abstract
The conserved protein kinase mTOR (mechanistic target of rapamycin) responds to diverse environmental cues to control cell metabolism and promote cell growth, proliferation, and survival as part of two multiprotein complexes, mTOR complex 1 (mTORC1) and mTORC2. Our prior work demonstrated that an alkaline intracellular pH (pHi) increases mTORC2 activity and cell survival in complete media in part by activating AMP-activated protein kinase, a kinase best known to sense energetic stress. It is important to note that an alkaline pHi represents an underappreciated hallmark of cancer cells that promotes their oncogenic behaviors. In addition, mechanisms that control mTORC1 and mTORC2 signaling and function remain incompletely defined, particularly in response to stress conditions. Here, we demonstrate that an alkaline pHi increases phosphatidylinositide 3-kinase (PI3K) activity to promote mTORC1 and mTORC2 signaling in the absence of serum growth factors. Alkaline pHi increases mTORC1 activity through PI3K-Akt signaling, which mediates inhibitory phosphorylation of the upstream proteins tuberous sclerosis complex 2 and proline-rich Akt substrate of 40 kDa and dissociates tuberous sclerosis complex from lysosomal membranes, thus enabling Rheb-mediated activation of mTORC1. Thus, alkaline pHi mimics growth factor-PI3K signaling. Functionally, we also demonstrate that an alkaline pHi increases cap-dependent protein synthesis through inhibitory phosphorylation of eIF4E binding protein 1 and suppresses apoptosis in a PI3K- and mTOR-dependent manner. We speculate that an alkaline pHi promotes a low basal level of cell metabolism (e.g., protein synthesis) that enables cancer cells within growing tumors to proliferate and survive despite limiting growth factors and nutrients, in part through elevated PI3K-mTORC1 and/or PI3K-mTORC2 signaling.
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Affiliation(s)
- Dubek Kazyken
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, USA.
| | - Stephen I Lentz
- Department of Internal Medicine, Division of Metabolism, Endocrinology, and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Maxwell Wadley
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Diane C Fingar
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, USA.
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